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  • 2020-2022
  • 1980-1984  (48)
  • 1965-1969
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  • 1981  (41)
  • 1980  (7)
  • Genetics
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 17 (1981), S. 167-181 
    ISSN: 1432-1432
    Keywords: Evolution ; Genetics ; REH theory ; Mutations ; Natural selection ; Nucleic acids ; Proteins ; Paleogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have independently repeated the computer simulations on which Nei and Tateno (1978) base their criticism of REH theory and have extended the analysis to include mRNAs as well as proteins. The simulation data confirm the correctness of the REH method. The high average value of the fixation intensity μ2 found by Nei and Tateno is due to two factors: 1) they reported only the five replications in which μ2 was high, excluding the forty-five replications containing the more representative data;and 2) the lack of information, inherent to protein sequence data, about fixed mutations at the third nucleotide position within codons, as the values are lower when the estimate is made from the mRNAs that code for the proteins. REH values calculated from protein or nucleic acid data on the basis of the equiprobability of genetic events underestimate, not overestimate, the total fixed mutations. In REH theory the experimental data determine the estimate T2 of the time average number of codons that have been free to fix mutations during a given period of divergence. In the method of Nei and Tateno it is assumed, despite evidence to the contrary, that every amino acid position may fix a mutation. Under the latter assumption, the measure X2 of genetic divergence suggested by Nei and Tateno is not tenable: values of X2 for theα hemoglobin divergences are less than the minimum number of fixed substitutions known to have occurred. Within the context of REH theory, a paradox, first posed by Zuckerkandl, with respect to the high rate of covarion turnover and the nature of general function sites in proteins is resolved.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-069X
    Keywords: Genetics ; Hair dysplasia ; Scanning electron microscopy ; Uncombable hair syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0983
    Keywords: Protoplast ; Fusion ; Mitochondrial ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a protoplast fusion technique we have been able to locate to the mitochondrial genome of the asporogenous yeast Torulopsis glabrata mutations conferring resistance to oligomycin, antimycin and diuron. When two strains differing in the size of their mtDNAs were fused the mitochondrial markers from the parent with the larger mtDNA (71–91) were transmitted predominantly among the fusion products. Both genetical and physical evidence support the occurrence of recombination in T. glabrata mitochondrial genome. Segregation of the mitochondrial genome appears to take place before the separation of the first bud from the fusion product.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 4 (1981), S. 177-180 
    ISSN: 1432-0983
    Keywords: Genetics ; Yeasts, protoplasts ; Saccharomyces ; Hansenula
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Protoplasts of petites of strains 625-CI of Saccharomyces diastaticus and NCYC 1085 of Saccharomyces cerevisiae, originally obtained from the National Collection of Yeast Cultures, England, were fused with protoplasts of Candida pseudotropicalis, Saccharomyces rosei, Yaccharbmycesmontanus, Pichiamembranefaciens, Hansenula anomala, Hansenula capsulata, and Schizosac-charomyces pombe. The respiratory-competent products of the fusions were selected on the basis of using at least one of the carbon sources utilized by the petite parent and not by the other. The products of the fusion of C. pseudotropicalis x 1085(p−) consisted of two cell types; an oval cell which utilized both lactose and maltose and fermented lactose vigorously, and a cylindrical form which fermented maltose slowly. The S. rosei x 1085(p−) hybrids had acquired the ability to metabolize and ferment galactose, and to ferment maltose, from the petite parent. The P. membranaefaciens x 625(p−) hybrids acquired the ability to metabolize galactose, sucrose and maltose, but fermented only glucose, weakly, like the P. membranaefaciens parent strain. The H. capsulate x 625(p−) hybrids, unlike the hybrids with P. membranaefaciens or S. rosei, resembled the petite parent morphologically and also had the fermentative abilities of this strain (galactose, maltose, sucrose and starch), and the ability to ferment starch was considerably enhanced. The S. montanus x 625(p−) hybrids acquired the ability to utilize starch. Schizosaccharomyces pombe x 625(p−) hybrids resembled S. pombe morphologically, but had the ability to metabolize galactose and starch. Some of the asci produced by these hybrids contained abnormal numbers of spores. H. anomala x 624 x(p−) hybrids fermented starch, though weakly.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 60 (1981), S. 229-236 
    ISSN: 1432-2242
    Keywords: Glutenin ; Triticum ; Genetics ; SDS ; Polyacrylamide-gel-electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The high-molecular-weight (HMW) subunits of glutenin from about 185 varieties were fractionated by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). About 20 different, major subunits were distinguished by this technique although each variety contained, with only a few exceptions, between 3 and 5 subunits. Further inter-varietal substitution lines to those already described (Payne et al. 1980) were analysed and the results indicate that all the HMW subunits are controlled by the homoeologous group 1 chromosomes. All hexaploid varieties studied except ‘NapHal’ contained two major subunits controlled by chromosome 1D. Their genes were shown to be tightly linked genetically for only four different types of banding patterns were observed. The nominal molecular weights determined after fractionation in 10% polyacrylamide gels were between 110,000 and 115,000 for the larger of the two subunits and between 82,000 and 84,000 for the smaller. One quarter of the varieties contained only one major HMW subunit controlled by chromosome 1B whereas the rest had two. The chromosome 1B subunits were the most varied and nine different banding patterns were detected. All the subunits had mobilities which were intermediate between those of the two chromosome 1D-controlled subunits. Only two types of HMW subunit controlled by chromosome 1A were detected in all the varieties examined; a single variety never contained both of these subunits and 40% of varieties contained neither. The chromosome 1A-controlled subunits had slightly slower mobilities in 10% gels than the largest HMW subunit controlled by chromosome 1D. About 100 single grains were analysed from each of five different crosses of the type (F1 of variety A × variety B) × variety C. The results indicate that the genes on chromosome 1B which control the synthesis of subunits 6, 7, 13, 14 and 17 are allelic, as are the genes of the chromosome 1A-controlled subunits, 1 and 2.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 60 (1981), S. 265-268 
    ISSN: 1432-2242
    Keywords: Agrocybe ; Genetics ; Fruiting ; Biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the edible white rot fungus Agrocybe aegerita the threshold from mycelial growth to fruit body formation is under control of a single gene in both monokaryons and dikaryons. The allele su opens the pathway for fruiting and allows the subsequent expression of the fruiter genes fi+ (fruit body initials) and fb + (fruit bodies). Its allele, su +, suppresses monokaryotic fruiting completely and restricts dikaryotic fruiting drastically. The detection of this threshold gene su +/su and its action and interactions has practical implication in that an opportunity for concerted breeding is created. First results indicate that the fruiter genes are involved in two essential parameters of productivity. Both time of fruiting and biomass production depend on the two fruiter genes fi + and fb +. Comparable results obtained with two other basidiomycetes suggest that the genetic control of fruiting in Agrocybe aegerita is a general mechanism which may be made use of in breeding work with other basidiomycetes of economic value.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Environmental biology of fishes 6 (1981), S. 357-360 
    ISSN: 1573-5133
    Keywords: Behaviour ; Esterase ; Evolution ; Genetics ; Isozymes ; Stock structure ; Schools ; Starch gel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Heterogeneous gene frequencies of Est-1 across groups ofNotropis cornutus provide evidence of behaviourally imposed restrictions on stock structuring. Positive fixation indices (F1S = 0.056 and F1T = 0.085) were reflected by a deficiency of heterozygotes for pooled groups. The degree of subdivision ofN. cornutus stocks cannot be evaluated with the present evidence. but it is likely that their schooling behaviour is associated with significant genotypic structuring of the species.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0192-253X
    Keywords: nuclear differentiation ; cytoplasmic inheritance ; Paramecium tetraurelia ; mating type ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In P. tetraurelia each cell is determined to express only one of the two complementary mating types, O and E. This determination is under cytoplasmic control and seems to be achieved only by the commitment or noncommitment to the expression of mating type E. All the previously known mutations affecting the differentiation of mating type prevent the expression of the E mating type (O-restricted mutations) without affecting the determination process. An E-restricted mutation was obtained: mtFE. Its phenotypic properties indicate that the mutation affects the determination process itself. When an O cell becomes mtFE/mtFE it acquires the E mating type and an E-determining cytoplasm. We propose that this constitutive determination for the E mating type is due to the inefficiency of a factor which is normally active in an O cell. This factor would act like a repressor and stabilize the E functions under an inactive state.
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 279-290 
    ISSN: 0192-253X
    Keywords: temperature-sensitive mutant ; cytokinin ; hormonal metabolism ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Developmental controls of morphological mutants of Phaseolus vulgaris L. conditioned by two independent loci, DL1 and DL2, were examined through grafting experiments and hydroponic studies. Phenotypes of mutant classes were duplicated by unions of scions and stocks derived from different genotypes. Results indicate that DL1 and DL2 regulate a root and shoot factor respectively, contributing to the mutant types. The allelic dosages of DL1 in the root and DL2 in the shoot rather than the genotype of the whole plant per se determine the severity of the mutant expression. Plants heterozygous for both loci with a temperature-sensitive expression of the mutant phenotype were used to determine physiological components involved. The primary abnormal developmental event associated with the appearance of mutant phenotypes, the restricted root growth at high temperature, could be overcome by the addition of cytokinin in hydroponic solution. These observations suggest that DL1 and DL2 may be related to the regulation of hormonal function or metabolism.
    Additional Material: 8 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 12
    ISSN: 0192-253X
    Keywords: suspensive and adhesive teratoma cells ; teratoma embryoid bodies ; cell differentiation ; endogenous prostanoid biosynthesis ; long-chain fatty acyl CoA derivatives ; mass fragmentography ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Attachment of the cell surface to a substratum may play a critical role in initiating some cellular developmental commitments and in sustaining differentiation of cells that have already been specialized. Embryoid bodies of teratoma OTT6050 were divided, on day 10 of initial culture, into myogenic adhesive cells which were already (at day 6) characterized by endogenous prostaglandin (PG)I2 formation and little-specialized suspensive cells which formed only thromboxane (TX)B2 in the same culture system. Since at day 10 both cell types reached a stationary phase in which the nature of each cell was mature enough for the analyses with mass fragmentographic technique and gas chromatography- mass spectrometry (GCMS), the total levels of predominant long-chain fatty acyl CoA (acyl CoA) derivatives could be measured comparatively as methyl esters after methanolysis. It was found as a result of major differentiation that adhesive cells had a rather low ratio of arachidonyl CoA to stearyl CoA, although adhesive cells accumulated a larger total amount of acyl CoA derivatives than that accumulated in suspensive cells.
    Additional Material: 5 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 99-111 
    ISSN: 0192-253X
    Keywords: CIPC as a mitotic inhibitor of Dictyostelium ; inhibition of Dictyostelium development by CIPC ; CIPC-resistant mutants ; Dictyostelium ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The anti-mitotic herbicide isopropyl N-(3-chlorophenyl) carbamate (CIPC) prevents the growth of amoebae of Dictyostelium discoideum without killing the cells for a period of time equivalent to one generation. During in-hibition, amoebae accumulate in prophase and metaphase of mitosis. After removal of CIPC, they continue through mitosis and then divide.The addition of CIPC to amoebae under starvation conditions prevents aggregation and concomitant cell elongation. The cells, however, do not lose their ability to adhere to a surface, and they remain viable. When CIPC is added to amoebae which have formed streams, it leads to the disintegration of streams into small clusters of cells and to a loss of cell elongation.Post-aggregation stages of development can be inhibited by CIPC at the mound, slug, or Mexican hat stages. Slugs break apart into distinct aggregates.Mutants resistant to CIPC can be obtained easily. Among these mutants, many become temperature sensititive for growth (27°C) or development (27°C or 15.5°C). Others show various abnormalities at the normal temperature (22°C). Most mutants are cross resistant to the microtubule inhibitors nocodazole and thiabendazole, and some are also resistant to CIPC during development.
    Additional Material: 7 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 147-158 
    ISSN: 0192-253X
    Keywords: triplo-lethal locus ; Tpl ; gene-dosage ; X chromosome ; Drosophila melanogaster ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Only a single locus (Tpl) is known in the Drosophila melanogaster genome that leads to early lethality when present as a heterozygous duplication (three doses) or deficiency (one dose). We report the recovery of third instar larvae (and of occasional adults) carrying a duplication for the triplo-lethal locus, Dp(Tpl). Karyotype analysis of the larvae showed that the individuals surviving were almost entirely 3X;2A metafemales. We examined the question of whether the entire X or a single X locus was a major factor permitting survival. X-Y translocations were used to produce females hyperploid for different portions of the X and carrying Dp(Tpl). Analysis of metaphase chromosomes by quinacrine fluorescence pattern indicates that the X chromosome region between 6D and 7DE must be present in an extra copy to enhance the survival of Tpl duplication-bearing females. Another type of experiment suggests that it is the region between 7C and 7DE which is essential.
    Additional Material: 4 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 131-146 
    ISSN: 0192-253X
    Keywords: rat chimeras ; hooded pigmentation ; melanocyte ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: New, improved media and procedures for making rat chimeric embryos and culturing them in vitro have been developed. We have produced 27 rat chimeras: 20 males and 7 females. This ratio of males to females is consistent with that seen in mouse chimeras, suggesting that rat sex chimeras develop as phenotypic males. By aggregating embryos containing appropriate genetic markers for pigment cell differentiation, it is possible to produce chimeras that elucidate the site of action of the hooded gene. The coat color patterns of black ↔ black hooded chimeras display a white belly spot. In black ↔ albino hooded chimeras, small patches of white hair appear on the head and a large white spot occurs on the belly. Black ↔ agouti hooded chimeras display both agouti and nonagouti pigmentation over the entire surface of the chimera. These animals are fully pigmented with no white spots. In black ↔ albino non-hooded chimeras, rather small irregular patches of black and white hairs are distributed throughout the pelage. Histological examination of sections of hair follicles obtained from the white areas in the head of black ↔ albino hooded chimeras revealed amelanotic melanocytes. On the other hand, hair bulbs from the white belly spots do not contain any such melanocytes. Thus the white hairs of the head are due to the presence of albino melanocytes, but the white hairs of the belly are due to the total absence of melanocytes. All these observations are consistent with the conclusion that the hooded gene acts within melanoblasts, probably to retard their migration from the neural crest and/or to prevent their entrance into the hair follicles of the white areas of hooded rats.
    Additional Material: 7 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 171-183 
    ISSN: 0192-253X
    Keywords: sperm ; F9 antigen ; T/t-complex ; immunolabeling ; scanning electron microscopy ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The antigens defined by conventional syngeneic antiserum against F9 embryonal carcinoma cells were localized on mature sperm using immunolabeling and scanning electron microscopy. Labeling patterns were compared for normal (+ / +) mice and mice bearing recessive t-haplotypes. The results showed that antigens detected by intact anti-F9 antiserum are expressed similarly in all genotypes, except for sperm from mice bearing the t12-haplotype where the frequency of labeled cells was reduced. Labeling with the IgM fraction of anti-F9 antiserum was lower on sperm from all t-genotypes examined, with sperm from + /t12 males showing the most marked reduction. In all cases, the labeling patterns were similar, and included a labeling of the whole sperm head with complete anti-F9 antiserum and a restriction of the label to the postacrosomal region when the IgM fraction was used.
    Additional Material: 5 Ill.
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  • 17
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 219-222 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 49-73 
    ISSN: 0192-253X
    Keywords: determination ; Drosophila ; haltere disc ; homeotic mutation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mutations at the bithorax locus transform anterior haltere tissue into anterior wing. These transformations could in principle be due to the mutations altering either the expression or cell heredity functions of determination. I have studied two alleles of the bithorax locus bx3 and bx34e using disc culture techniques and found that both produce their transformations by altering the expression of the determined state. I have also found that the expression of the temperature-sensitive allele, bx34e, can be altered by temperature shifts during the culture period. Evidence has been obtained that suggests that such changes in expression do not require growth or cell division.
    Additional Material: 5 Ill.
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  • 19
    ISSN: 0192-253X
    Keywords: temporal genes ; GPDH isozymes ; regulation ; development, Drosophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The complete developmental program of glycerol-3-phosphate dehydrogenase in wild type Drosophila is described with respect to activity, isozyme expression, and GPDH-specific CRM. Variants of this developmental program have been isolated from natural populations which affect the rate of accumulation of only the GPDH-3 isozyme in both the larval and adult stages of development. This activity variation segregates as a single gene which is tightly linked to the structural element on Chromosome II, exhibits cis-control, and is tissue specific in expression. This gene meets all the criteria for temporal regulatory genes.
    Additional Material: 8 Ill.
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  • 20
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 21
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 159-170 
    ISSN: 0192-253X
    Keywords: Tetrahymena hegewischi ; timing of maturity ; cellular differentiation ; genetic ; environmental variation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The development of sexual maturity has been studied in Tetrahymena hegewischi. Progeny lines do not typically change from immaturity to mating with all different mating types during a single test interval, but about 30% do mature abruptly. Some testers are more likely than others to participate in the earliest mating reactions of progeny lines which do not mature abruptly. Subcaryonidal vegetative pedigrees of 10 pairs from 4 crosses revealed considerable intrapair variation in the time, measured in fissions, of maturity. The average intrapair coefficient of variation was 20%. A nested ANOVA revealed significant genomic effects on the immaturity interval, but no significant cytoplasmic or caryonidal effects; 56% of the total variation was non-genomic. Growth in different environments had highly significant effects on the immaturity interval. Subclones grown at 27°C with alternate day transfers took on the average 2 to 3 times as many fissions to mature as sister subclones grown at 27°C with daily transfers. Subclones grown at 18°C or 34°C and transferred on alternate days had intermediate maturation times. The greatest range in the immaturity interval among lines of the same genotype was from 34 to 143 fissions. The development of maturity in this species involves genetic control of timing, but the genetic differences are obscured by a large amount of intraclonal variation and sensitivity to the environment.
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  • 22
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981) 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 23
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 369-383 
    ISSN: 0192-253X
    Keywords: Dictyostelium discoideum ; aggregation-deficient mutants ; intracellular cAMP ; adenylate cyclase ; defective spore differentiation ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Forty aggregation-deficient mutants of Dictyostelium discoideum were screened for changes in intracellular cAMP during the first 10 hr of starvation. The pools in 39 of the mutants remained low and relatively static during this period. However, amoebae of one mutant, strain HC151, exhibited significantly elevated levels of intracellular cAMP during vegetative growth and for several hours after starvation. A more detailed analysis of this mutant indicated that the elevated cAMP pools in these cells are a consequence of the premature appearance and partial activation of an adenylate cyclase. The mutation(s) altering adenylate cyclase regulation in this strain appears to map in linkage group IV. Complementation tests between strain HC151 and another mutant, HH201, which has recently been shown to produce an adenylate cyclase activity precociously [1], indicated that the mutations affecting adenylate cyclase activity in these strains map at different loci. Although both of these mutations behave recessively in heterozygous diploids with respect to gross development, an examination of early cAMP metabolism and terminal spore differentiation in these diploids suggest that these mutations are at least partially expressed during some stage(s) of the developmental cycle.
    Additional Material: 6 Ill.
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  • 24
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 35-48 
    ISSN: 0192-253X
    Keywords: proteoglycan ; micromelia ; avian embryo ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Embryos homozygous for the recessive lethal gene, micromelia-Abbott, develop a severe form of micromelia, a parrot-like beak, and hemorrhagic skin. Feather development is also retarded. The reduction in length of the long bones of the leg can be traced to their cartilaginous stage Quantitative analysis of sulfated proteoglycan (PGS), a major macromolecular component of cartilage matrix, reveals that mutant tibiae, femora, and sterna contain significantly less uronic acid per μg of DNA than normal rudiments, indicating reduced accumulation of PGS in the mutant. Incorporation of radioactive precursors into cartilage PGS is severely reduced in relatively early developmental stages of a particular organ, but this reduction becomes less severe in cartilage taken from the same rudiment at a later developmental stage. Analysis of the sedimentation rate of PGS in sucrose gradients reveals no difference between normal and mutant in all cartilaginous types at all ages. These results suggest that the quantity and not the quality of PGS is affected in this mutant. The observation that the addition of para-nitrophenyl-β-D-xyloside to the culture medium can stimulate glycosaminoglycan synthesis to normal levels is interpreted to mean that the reduced levels of PGS may be the result of a reduced availability of the xylosylated protein backbone for PGS.
    Additional Material: 4 Ill.
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  • 25
    ISSN: 0192-253X
    Keywords: alcohol dehydrogenase C2 ; isozymes ; temporal locus ; genetics ; chromosome 3 ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The tissue specificity of a proposed cis-acting temporal locus (Adh-3t), which regulates alcohol dehydrogenase C2 (ADH-C2) activity in mouse reproductive tissue extracts, has been examined in C5 7BL/6J, SM/J, F1 (SM/J × C5 7BL/6J) mice as well as in progeny of an (F1 [SM/J × C5 7BL/6J] × C5 7BL/6J) back-cross. Electrophoretic variants for ADH-C2, previously used to localize the gene (Adh-3) encoding this enzyme on chromosome 3, enabled the relative parental contributions to ADH-C2 phenotype in F1 and backcross mouse tissues to be determined. These analyses demonstrated that (1) stomach, kidney, lung, adrenals, seminal vesicles, epididymis, uterus, and ovary ADH-C2 is encoded by a single locus (Adh-3); Adh-3t is differentially active in various tissues, eg, lung exhibits no apparent activity whereas the temporal locus is fully active in seminal vesicles; (3) Adh-3t is probably differentically active in different cells of some tissues, eg, adrenals. Specific activity profiles of stomach and epididymal ADH-C2 during the neonatal development of C5 7BL/6J, SM/J, and F1 (SM/J × C5 7BL/6J) male mice supported the proposal for a cis-acting temporal locus for this enzyme. Genetic analyses examining segregation of Adh-3 and Adh-3t among backcross progeny suggested that these are distinct but closely linked loci, since one recombinant among 256 progeny was observed. Linkage data of Adh-3 with Va (varitint-waddler) and de (droopy ear) was also obtained, which suggested that Adh-3 is localized on chromosome 3 between Va and de.
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  • 26
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 357-367 
    ISSN: 0192-253X
    Keywords: amphibian hybrids ; exogastrulation ; hybrid lethality ; nucleocytoplasmic interactions ; triploidy ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hybrids between species frequently arrest early in development. In the frog hybrid Rana catesbeiana female × Rana clamitans male, the embryo shows a characteristic development to an exogastrula which dies. This hybrid can be rescued by pressure suppression of the second polar body, which results in the addition of another haploid set of R catesbeiana chromosomes to the embryo. The triploid hybrid expresses genes from both species and can develop normally through metamorphosis. The results show that an R catesbeiana egg containing a full haploid set of R clamitans chromosomes is capable of development and that the usual developmental arrest caused by the R clamitans genome responds to chromosomal dosage.
    Additional Material: 10 Ill.
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  • 27
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 203-218 
    ISSN: 0192-253X
    Keywords: cytokinesis ; fusome ; intercellular bridges ; oogenesis ; sterility ; tumor mutations ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ethyl methane sulfonate-induced mutation, fs(1)1621, resides at 11.7 on the genetic map and within segment 4F1-5A1 of the cytological map of the X chromosome. When homozygous, fs(1)1621 renders females semisterile but has no effect on their viability; nor does it affect the viability or fertility of hemizygous males. Heterozygous females are fertile and have cytologically normal ovaries. The ovaries of homozygous females first produce normal oocytes, which, if fertilized, can develop into adult males or females. After this period, ovarian chambers containing only pseudonurse cells are formed, and finally mutant germaria produce only tumors. These contain hundreds to thousands of cells that appear to be derived from germarial cystocytes, because they occasionally form clones of interconnected cells and also can differentiate into endopolyploid pseudonurse cells. Raising the temperature speeds the rate at which tumors form; lowering it increases the probability of pseudonurse cell differentiation. Df(1)C159 includes fs(1)1621. The pattern of ovarian chamber production is more temperature sensitive in hemizygous females than in homozygous ones. The morphology of hemizygous tumors and the number of dividing cells within them also differ from homozygotes. These observations support the hypothesis that fs(1)1621 is producing a product, that less is produced by one gene than by two, and that the product plays a role in the mitosis and cytokinesis of ovarian cystocytes.
    Additional Material: 6 Ill.
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  • 28
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 237-252 
    ISSN: 0192-253X
    Keywords: Drosophila ; embryonic cultures ; protein synthesis ; stage specific ; differentiation ; two-dimensional gel electrophoresis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The patterns of proteins synthesized during embryonic development in Drosophila melanogaster have been examined by two-dimensional gel electrophoresis. Primary cell cultures prepared from donor embryos synchronized to ± 1 hr were labeled with [35S]methionine at 5, 11.5, 14.5, and 26 hr after oviposition. Of approximately 400 to 500 proteins detected, the synthesis of about 50 is developmentally modulated. The greatest number of changes in the synthesis of stage-specific proteins occurs at 11.5 and 14.5 hr after oviposition, periods just prior to and during the times of the greatest overt morphological and biochemical changes. At 11.5 hr, 35 stage-specific proteins are synthesized, including 19 that are not present at the previous stage examined. At 14.5 hr, 34 stage-specific proteins can be detected, including 11 newly synthesized proteins. However, 12 proteins from the previous stage are no longer synthesized. At the completion of embryonic differentiation, at 26 hr, no new proteins are synthesized and the synthesis of many present in earlier stages has decreased or stopped. Comparison of patterns of embryonic proteins to those synthesized by two Drosophila continuous cell lines reveals that the majority of proteins are common to all. However, only about 40% of the embryonic stage-specific proteins are present in either cell line. In addition, there are several proteins unique to each cell line that are not observed in any of the embryonic stages.
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  • 29
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 1-12 
    ISSN: 0192-253X
    Keywords: β-galactosidase ; preimplantation ; mouse ; Bgl ; paternal effect ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Lysosomal acid hydrolase expression during preimplantation mouse embryogenesis has proved useful in estimating when mRNA transcription commences during this period. Previous work from this laboratory has shown that α-galactosidase and β-glucuronidase undergo 50- to 100-fold increases in activity between the two-cell stage and the blastocyst stage [1, 2]. Here we show that β-galactosidase activity levels undergo a similar change. We also demonstrate that mouse strains with the Bgl-sh allele produce cleavage stage embryos with 2-4-fold higher activity levels than strains with the Bgl-sd allele. Bgl has been shown to control β-galactosidase levels in adult mouse tissues [3]. Unfertilized egg β-galactosidase levels are also regulated by Bgl, but loci distant from Bgl modify egg expression. The distant sites are not observed to act during cleavage. Hybrid embryos (Bgl-sd/h) show intermediate activity levels to the parental types. The timing of the deviation of hybrid embryo β-galactosidase activity levels from maternal-type activity levels is used to estimate when transcription of genes governing β-galactosidase expression occurs.
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  • 30
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 23-34 
    ISSN: 0192-253X
    Keywords: Paramecium tetraurelia ; trichocysts, nuclear differentiation ; cytoplasmic inheritance ; determination ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The mtFE mutation isolated in Paramecium tetraurelia affects mating type differentiation, trichocyst excretion, and viability. Its effect on mating type has already been shown to correspond to a restriction to the E mating type interpreted by an inefficiency of nuclear O-determining factors. In this paper we study the other two phenotypic characteristics whose hereditary transmission displays two unusual features. (1) In crosses between a wild-type strain and the mutant strain, the mutant characteristics do not reappear in F2 in the wild-type cytoplasmic lineage but only in F3 after the homozygous clones have undergone an additional nuclear reorganization. (2) Some F2 wild-type clones, in the mutant cytoplasmic lineage, retain some of the phenotypic characteristics of the mutant. We propose that the mtF gene product plays a role in the control of several macronuclearly differentiated functions.
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  • 31
    Electronic Resource
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 75-87 
    ISSN: 0192-253X
    Keywords: Drosophila melanogaster ; homoeosis ; imaginal discs ; aldehyde oxidase ; pattern formation ; compartments ; selector genes ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In a study of the regulation of enzyme patterns in imaginal discs the aldehyde oxidase pattern was determined for some homoeotic mutations of D. melanogaster. Earlier indications that suggested that this pattern follows the determinitive state of compartments within imaginal discs were confirmed by the aldehyde oxidase (AO) pattern of both the wing and haltere discs from en1; bx3, en1; pbx, and en1; bx3 pbx larvae and the antennal discs from Antp73b and ssa larvae.We additionally analyzed whether AO activity depended on the determinative state of an entire compartment or was expressed autonomously in clones. Homozygous engrailed clones were induced by mitotic recombination. From the AO clones found in normally negative areas of the posterior compartment it was concluded that enzyme activity depended upon the determinative state of the cells and was not a function of the compartment as a whole.The results are described with reference to a scheme in which compartmental and subcompartmental selector genes are thought to determine a binary code on which AO patterns depend.
    Additional Material: 6 Ill.
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  • 32
    ISSN: 0192-253X
    Keywords: Drosophila ; dopa decarboxylase ; female fertility ; temperature sensitive lethal mutant ; differential tissue-specific responses to temperature ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The mutation Ddcts1 effects female sterility when homozygous, hemizygous, or heterozygous over a series of Ddc null alleles (Ddcx) indicating that some aspect of Ddc gene function is necessary for female fertility. Ovary transplant experiments demonstrate that the female sterility phenotype is ovary autonomous. Two to 3% of the total DDC activity measurable in newly hatched females is localized in their previtellogenic ovaries. The degree to which females heterozygous for Ddcts1 over different Ddc null alleles are fertile at 22°C reflects a continuous spectrum of allelic complementation similar to that observed for the effects of these genotypes on viability at 30°C. Fertility of all the Ddcts1/Ddcx females tested is significantly depressed at 30 vis-a-vis 22°C providing evidence that it is the DDC enzyme activity itself which is required for female fertility. Ddcts1/Ddcts1 homozygous and Ddcts1/Df hemizygous females are nonconditionally, completely sterile at 18, 20, 22, 25, and 30°C. Although all homo- and hemizygous females do lay some eggs, no evidence of embryogenesis or fertilization has ever been detected. The absolute, nonconditional sterility of Ddcts1 homo- and hemizygous females stands in stark contrast to the conventional temperature dependent effects of these same genotypes on viability and to the temperature sensitive effects of Ddcts1/Ddcx heterozygous females on both fertility and viability. Reasons for these tissue-specific and genotypic differences are discussed.
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  • 33
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 253-267 
    ISSN: 0192-253X
    Keywords: myxomycete ; Physarum polycephalum ; mating type ; sexual compatibility ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The conversion of the uninucleate amoebal form of Physarum polycephalum to the multi-nucleate plasmodial form is under the control of a genetic region which contains matA (or mt), a determinant of mating specificity. The region is the site of most gad mutations, which give amoebae the ability to produce plasmodia in clones without mating (ie, to self). In the present study, nonselfing revertants were isolated from two matA2-derived gad mutants and two matA3-derived gad mutants. Some revertants were found to have regained exactly, or nearly, the same phenotype as the original matA2 or matA3 strain. Others expressed new mating types, having gained the ability to mate with strains of the parental matA type. The results are compatible with a model in which new mating types arise from forward mutations (gad) and back mutations (npf or no plasmodium formation) occurring successively in a single gene, matA.
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  • 34
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    Developmental Genetics 2 (1981), S. 269-277 
    ISSN: 0192-253X
    Keywords: β-glucuronidase ; androgen ; receptor ; development ; mouse ; kidney ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During postnatal development of mouse kidney the androgen responsiveness of epithelial cells for β-glucuronidase induction, cellular hypertrophy, and other enzyme inductions appears coincidentally with a rise in androgen receptor protein. Initially, a low level of receptor is present but no response is seen. Beginning at about 12 days of age responsiveness begins to increase, reaches a half-maximal level at 18-20 days, and full responsiveness by 28-30 days. The limiting factor appears to be levels of androgen receptor protein.Our experiments shed no light on the question of why each androgen responsive cell type in the organism differentiates the capacity to induce a different array of proteins. However, they do suggest that responsiveness of the β-glucuronidase gene does not appear until a minimum threshold level of receptor is exceeded, and that the response of the gene may not be saturated even at the highest levels of receptor reached.
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  • 35
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    Developmental Genetics 2 (1981), S. 305-315 
    ISSN: 0192-253X
    Keywords: X-chromosome inactivation ; mouse ; PGK-1 ; embryonic cell lineage ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have used a sensitive electrophoretic technique for estimating the activity, or ratio, of two allozymes of the X-chromosome-linked enzyme phosphoglycerate kinase (PGK-1), in order to investigate the randomness of X-chromosome expression in the derivatives of the three primary cell lineages of the early mouse conceptus. The maternally derived Pgk-1 allele is preferentially expressed in the derivatives of the primitive endoderm and trophectoderm lineages at 6 1/2 days post coitum in Pgk-1a/Pgk-1b heterozygous conceptuses, and in the one informative 5 1/2-day heterozygous conceptus analysed. This evidence for preferential expression of the maternally derived X chromosome (Xm), so soon after the time of X-chromosome inactivation, favors the possibility that the preferential expression of Xm is a consequence of primary non-random X-chromosome inactivation, rather than a secondary selection phenomenon. The majority of embryos analysed at 4 1/2 and 5 1/2 days pc produced only a single PGK-1 band, corresponding to the allozyme produced by the Pgk-1 allele on Xm, although 50% of these embryos should have been heterozygous females. Possible explanations are discussed.
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  • 36
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 319-336 
    ISSN: 0192-253X
    Keywords: maize ; mitochondrial DNA ; recombinant DNA ; cms-T ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Recombinant DNA and hybridization techniques have been used to compare the organization of mitochondrial DNA (mtDNA) from normal (N) and Texas male sterile (T) cytoplasms of maize. Bam H1 restriction fragments of normal mtDNA were cloned and used in molecular hybridizations against Southern blots of Bam H1 digested N and T mtDNA. Fifteen of the 35 fragments were conserved in both N and T as indicated by hybridization to comigrating bands in their restriction patterns. Only three fragments produced autoradiographs whose differences could reasonably be attributed to single changes in the cleavage site of the enzyme while approximately half (17/35) of the clones resulted in more complicated differences between N and T. The autoradiographs produced by these 17 clones indicated multiple cleavage site changes and/or sequence rearrangements of the mtDNA. Patterns of six of these 17 clones indicated partial duplication of the sequence and two showed variation in the intensity of hybridization between N and T, which may be related to the molecular heterogeneity phenomenon found in maize mitochondrial genomes. The large proportion of changes observed between N and T mtDNA indicates that rearrangements may have played an important role in the evolution of the maize mitochondrial genome.
    Additional Material: 7 Ill.
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  • 37
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 185-202 
    ISSN: 0192-253X
    Keywords: somatic DNA alteration ; nuclear differentiation ; mating types ; ciliate genetics ; immunoglobulin genes ; Tetrahymena thermophila ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Experimental data on mating type determination in T. thermophila, collected by Nanney, Allen, and their collaborators over a period of 25 years, are reinterpreted in the light of our current understanding of macronuclear genetics. A strong case is developed supporting the idea that mating type determination involves the developmental alteration of somatic DNA that occurs regularly in developing macronuclei in conjugating pairs. A. testable DNA deletion/splicing model is developed that although based on a few simple, plausible assumptions, explains the observations remarkably well. The model is in (at least) superficial analogy to the mechanism that must be involved to explain the somatic differentiation and alteration of DNA sequences that ultimately constitute an expressed vertebrate immunoglobulin gene. Because of the genetic, biochemical, and micromanipulative versatility of Tetrahymena, it may well turn out to be a uniquely suitable microbial eukaryotic experimental system for the study of developmental alterations of somatic DNA.
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  • 38
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 317-317 
    ISSN: 0192-253X
    Keywords: Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
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  • 39
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 291-303 
    ISSN: 0192-253X
    Keywords: mouse ; trisomy ; gene dosage ; enzyme activity pattern ; phosphoglycerate mutase (PGAM) ; glutamate oxaloacetate transaminase (GOT) ; isozyme ; developmental pattern ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Activity patterns of cytosolic and mitochondrial enzymes of carbohydrate and amino acid metabolism have been measured in murine trisomy 19. In spite of marked hypoplasia, no significant alterations of the patterns (per gram of organ weight) were observed, with the exception of glutamate oxaloacetate transaminase (GOT-1), and phosphoglycerate mutase (PGAM). Clear-cut gene dosage effects in liver, brain, heart, skeletal muscle, and erythrocytes of fetal and newborn mice, confirm the assignment of GOT-1 to chromosome 19. Data obtained for PGAM demonstrate that one of the two different subunits leading to organ-specific isozyme patterns of the dimer enzyme protein is coded on chromosome 19 (gene Pgam-1). Dosage effects are fully expressed in liver, brain, and erythrocytes (AA-type isozyme), but not in skeletal muscle (BB-type isozyme). Dosage effects on the hybrid AA-AB-BB-isozyme pattern in the course of development of the heart muscle, were demonstrated by means of quantitative activity measurement after electrophoretic separation. The comparison of enzyme patterns of eusomic and trisomic erythrocytes, produced after injection of fetal stem cells into irradiated adult carriers (transplantation chimaeras), revealed enzyme activity ratios that were similar to those produced by erythrocytes of adult euploid and trisomic mice. This is in agreement with the chromosome assignments and dosage effects mentioned above.
    Additional Material: 5 Ill.
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  • 40
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 349-356 
    ISSN: 0192-253X
    Keywords: agouti locus ; lethal yellow gene ; MSH ; dibutyryl cyclic AMP ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Alleles at the agouti locus determines the type of pigment produced in hair-bulb melanocytes. In order to analyze the mechanism of agouti gene function, an attempt was made to induce the shift in melanin synthesis in vitro. Skin explants from newborn yellow mice with genotype Ay/a were cultured with the method using membrane-filter and roller tube. Production of black pigment in the hair bulbs was observed when the explants were cultured in the presence of α-melanocyte stimulating hormone (α-MSH). Electron-microscopic observation indicates that the induced black pigments are eumelanin that is normally found in hair-bulb melanocytes of genotypically black mice. The eumelanin synthesis was also induced by cAMP, DbcAMP, or theophylline. This α-MSH-induced eumelanin synthesis was suppressed by actinomycin D or cycloheximide, suggesting that the α-MSH-induced eumelanogenesis requires de novo transcription and/or translation.
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  • 41
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    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 2 (1981), S. 385-405 
    ISSN: 0192-253X
    Keywords: allelic isozyme variants ; mammalian development ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The past decade has seen an explosion of interest in mammalian embryos. Techniques of molecular and genetic analysis coupled with advances in in vitro culture and experimental manipulation of mammalian embryos have provided important insights into mechanisms of embryogenesis. Many of these recent advances have been facilitated by the use of allelic isozyme variants as autonomous cell markers or representative gene products. Investigations aimed at exploring cell lineages and cell commitment, the timing and regulation of gene expression, X chromosome inactivation, and cell interactions have depended on the availability of appropriate isozyme variants. Results from such experiments are summarized here in order to demonstrate the usefulness of this approach and to stimulate its wider application in developmental biology.
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  • 42
    ISSN: 1432-0983
    Keywords: Chlamydomonas ; Chloroplast ; DNA ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The density, molecular weight, and cellular repetition of DNA molecules associated with the β-DNA satellite of the interfertile algae Chlamydomonas eugametos and C. moewusii are reported. The similarities between these values and those for the chloroplast DNA (cpDNA) in the related alga Chlamydomonas reinhardtii indicate that these satellites represent cpDNA. The buoyant densities of C. eugametos and C. moewusii cpDNAs are indistinguishable from one another, as are those of their respective nuclear DNAs. These densities differ slightly from the densities of the homologous components of C. reinhardtii whole cell DNA. All three species differ with respect to additional minor satellite DNAs and low molecular weight DNAs of unknown cellular location. Differences in the Aval and Smal restriction endonuclease fragmentation patterns of C. eugametos and C. moewusii cpDNAs were employed to study the inheritance of cpDNA in an F1 hybrid which had inherited a non-Mendelian streptomycin resistance marker (sr-2) from the C. eugametos mating-type plus (mt +) parent and in two homoplasmic mitotic segregants from a B 1 hybrid (F1 × C. moewusii) which had been initially heteroplasmic for the resistance marker. Although the cpDNA patterns in the F1 hybrid were similar to those of the C. eugametos ml 1 parent, important differences were noted which suggest that recombination between C. eugametos and C. moewusii cpDNA had occurred. Homoplasmic streptomycin resistant and sensitive mitotic segregants recovered from the B1 hybrid product reveal Aval restriction patterns similar to those of the respective resistant and sensitive parents. These data are consistent with the hypothesis that the sr-2 marker is located in cpDNA and that C. eugametos and C. moewusii cpDNA sequences can coexist in the same chloroplast and, at least sometimes, segregate without extensive recombination. The transmission of low molecular weight DNAs characteristic of C. moewusii but of unknown cellular origin shows no direct correlation with the transmission of the sr-2 marker.
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  • 43
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    Springer
    Journal of molecular evolution 16 (1980), S. 211-267 
    ISSN: 1432-1432
    Keywords: Nucleic acids ; Proteins ; Natural selection ; Genetics ; Nonrandom molecular divergence ; Nonrandom REH theory ; Evolution ; mRNA ; DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary REH theory is extended by deriving the theoretical equations that permit one to analyze the nonrandom molecular divergence of homologous genes and proteins. The nonrandomicities considered are amino acid and base composition, the frequencies with which each of the four nucleotides is replaced by one of the other three, unequal usage of degenerate codons, distribution of fixed base replacements at the three nucleotide positions within codons, and distributions of fixed base replacements among codons. The latter two distributions turn out to dominate the accuracy of genetic distance estimates. The negative binomial density is used to allow for the unequal mutability of different codon sites, and the implications of its two limiting forms, the Poisson and geometric distributions, are considered. It is shown that the fixation intensity — the average number of base replacements per variable codon - is expressible as the simple product of two factors, the first describing the asymmetry of the distribution of base replacements over the gene and the second defining the ratio of the average probability that a codon will fix a mutation to the probability that it will not. Tables are given relating these features to experimentally observable quantities inα hemoglobin,β hemoglobin, myoglobin, cytochromec, and the parvalbumin group of proteins and to the structure of their corre-sponding genes or mRNAs. The principal results are (1) more accurate methods of estimating parameters of evolutionary interest from experimental gene and protein sequence data, and (2) the fact that change in gene and protein structure has been a much less efficient process than previously believed in the sense of requiring many more base replacements to effect a given structural change than earlier estimation procedures had indicated. This inefficiency is directly traceable to Darwinian selection for the nonrandom gene or protein structures necessary for biological function. The application of these methods is illustrated by detailed consideration of the rabbitα -andβ hemoglobin mRNAs and the proteins for which they code. It is found that these two genes are separated by about 425 fixed base replacements, which is a factor of two greater than earlier estimates. The replacements are distributed over approximately 114 codon sites that were free to accept base mutations during the divergence of these two genes.
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  • 44
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    Psychopharmacology 72 (1980), S. 79-83 
    ISSN: 1432-2072
    Keywords: Avoidance ; Alcohol sensitivity ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract “Most affected” (MA) and “least affected” (LA) rats, bred for extremes in motor impairment following an alcohol challenge, differed in their performance on two active avoidance tasks. In two-way shuttle avoidance, the MA line performed significantly better than the LA group, both in terms of response latencies and percent avoidances. The inferior performance of the LA line persisted across the 15 days of testing, and appeared to reflect an difference in asymptotic performance levels. In one-way avoidance, the MA line showed significantly better acquisition than the LA group; however, this difference dissipated across the 3 days of training. When tested following alcohol administration in either the one-or two-way avoidance paradigm, the MA rats showed a greater performance deficit than LA animals. These data were interpreted as indicating the generality of alcoholrelated line differences to a situation motivated by aversive consequences. Moreover, the line difference in avoidance acquisition represents one of the few non-drug-related phenotypic differences that have been found in these lines. In previous generations, disparate base rates of wheel running have been reported, and the data presented here confirm and extend this finding.
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  • 45
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    Theoretical and applied genetics 57 (1980), S. 91-95 
    ISSN: 1432-2242
    Keywords: Cell culture ; Picloram-tolerance ; Genetics ; Uptake studies ; Nicotiana tabacum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A genetic and preliminary biochemical analysis has been performed on four picloram-tolerant mutants of Nicotiana tabacum that were isolated from cell cultures. The four mutations define three distinct linkage groups. Mutant seedlings incorporate radioactively labeled picloram normally and do not modify or degrade the herbicide in a manner that alters its solubility characteristics.
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  • 46
    ISSN: 1432-2242
    Keywords: Genetics ; Loci ; Powdery mildew ; Prolamin ; Recombination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The linkage relationship among the loci Hor1, Hor2, Ml-k and Ml-a on the short arm of chromosome 5 was studied by progeny testing the F2 generation of two crosses. The loci Hor1 and Hor2 code for polypeptides of the storage protein hordein (prolamin) and the loci Ml-k and Ml-a determine the resistance reaction with some powdery mildew fungi cultures. The order of the loci is Ml-k, Hor1, Ml-a, and Hor2, the first named being nearest the centromere. The recombination percentage between Hor1 and Hor2 was determined in the F1 and F2 generations in both crosses, the combined estimate being 7.4±0.9 per cent. The recombination percentage estimated between Ml-k and Hor1 was 4.0±1.3, between Hor1 and Ml-a, 5.3±1.1, and between Ml-a and Hor2, 6.1±1.2. The estimates involving the Ml- loci were all probably a little too high.
    Type of Medium: Electronic Resource
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  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 56 (1980), S. 5-9 
    ISSN: 1432-2242
    Keywords: Genetics ; Poultry ; Family selection ; Individual selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Responses to single trait selection on individual phenotype and sire-family mean phenotype for survivor's egg weight and rate of lay were measured for a single generation in 13 replicates. Each replicate-selection criterion-trait subclass consisted of eight sire families or 72 females measured and was reproduced from the best 25% of the families or individuals. The realized heritability of egg weight was 0.39 and that of rate of lay was 0.31, both of which were significantly greater than zero but not significantly different from the predicted values based on halfsib correlations in the base population. The standardized response to sire-family selection was less than the response to individual selection for both traits and the difference was significant for rate of lay (0.10; 0.31) but not for egg weight (0.22; 0.39). The predicted responses to sire-family selection were less than those for individual selection for both traits, and the observed responses to sire-family selection were not significantly different from the predicted values for either trait. These experimental results do not disagree with the theoretical expectations of the relative efficiencies of individual and sire-family selection.
    Type of Medium: Electronic Resource
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  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 58 (1980), S. 113-120 
    ISSN: 1432-2242
    Keywords: Glutenin ; Triticum ; Genetics ; SDS-polyacrylamide ; Gel-electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The electrophoretic mobilities of the high-molecular-weight (HMW) subunits of glutenin from 7 varieties were compared by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate (SDS). In total, 12 subunits were clearly resolved and they had nominal molecular weights of between 95,000 and 140,000. The chromosomes which control their synthesis were determined using monosomic lines and inter-varietal substitution lines. All subunits were shown to be controlled by the homoeologous group 1 chromosomes. Each variety contains between 3 and 5 HMW subunits; two are under the control of the 1D chromosome, 1 or 2 are controlled by chromosome 1B and 0 or 1 by chromosome 1A. The segregation of two 1D-controlled subunits of similar electrophoretic mobilities were analysed in the F2 progeny of crosses between ‘Chinese Spring’ and ‘Holdfast’. The results suggest that the genes which code for the two proteins are allelic.
    Type of Medium: Electronic Resource
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