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  • QTL  (5)
  • Cytoplasmic dynein
  • fracture
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    International journal of fracture 100 (2000), S. 401-408 
    ISSN: 1573-2673
    Schlagwort(e): Ferroelectric ceramic ; fracture ; energy criterion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract In the spirit of the Griffith's theory on mechanical fracture, a fracture criterion of ferroelectric ceramics in terms of energy analysis is proposed in this paper. The energy criterion is compared with the local energy release rate proposed by Gao et al. and the strain energy release rate of Park and Sun. In addition, the criterion can be used to explain why a positive electric field promotes cracking while a negative electric field can retard crack propagation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 93 (1996), S. 1083-1089 
    ISSN: 1432-2242
    Schlagwort(e): Dominant marker ; F2 family ; Linkage ; QTL ; Information function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Trans-dominant linked markers pairs (trans referring to the repulsion linkage phase) provide a model for inferring the F2 progeny genotype based upon both the conditional probabilities of F2 genotypes, given the F2 phenotype, and prior information on marker arrangement. Prior information of marker arrangement can be readily obtained from a linkage analysis performed on marker segregation data in a family resulting by crossing the F1 individual to a “tester” parent or else can be obtained directly from the gametes of the F1, or from recombinant inbred lines. We showed that a trans-dominant linked marker (TDLM) pair can be recoded as a “co-dominant megalocus” when the recombination fraction, r1, for apair of TDLMs is less than 0.05. We obtained a maximum-likelihood estimator (MLE) of the recombination frequency, r2, between a TDLM pair and a co-dominant marker in an F2 family using the EM algorithm. The MLE was biased. Mean bias increased as r1 and r2 increased, and decreased as sample size increased. The information content for r2 was compared to the information content of dominant and co-dominant markers segregating in an F2 family. It was almost identical with two co-dominant markers when r1≤0.01 and r2≥0.05. For larger values of r1, (0.05≤r1≤0.15) a TDLM pair provided 75%–66% of the information content of two co-dominant markers. Although dominant markers can be converted to co-dominant markers by a laborious process of cloning, sequencing, and PCR, TDLM pairs could easily substitute for co-dominant markers in order to detect quantitative trait loci (QTLs) and estimate gene action in an F2 family.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-2242
    Schlagwort(e): Key words AFLP ; Pseudo-testcross ; Eucalyptus ; QTL ; Vegetative propagation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  We have detected quantitative trait loci (QTLs) affecting vegetative propagation traits in Eucalyptus tereticornis and Eucalyptus globulus. Using amplified fragment length polymorphism (AFLP) genetic linkage maps, the inheritance of 199 markers was assessed in 94 F1 individuals with extreme adventitious rooting response, and in 221 randomly chosen F1 individuals. Phenotypes were scored in 1995 and 1996. QTL analyses were performed using chi-square tests (χ2), single-marker analysis (SMA), interval mapping (IM) and composite interval mapping (CIM). All approaches yielded similar QTL detection results. Three QTLs are hypothesized for mortality (MORT=% dead cuttings), nine for adventitious rooting (ROOT, RCT=% rooted cuttings relative to the surviving or total cuttings, respectively), four for petrification (PETR=% surviving unrooted cuttings), one for sprouting ability (SPR=number of stump sprout cuttings harvested in 1995) and four for the stability of adventitious rooting (STAB=absolute value of the difference ROOT95-ROOT96). All putative QTLs for MORT and PETR were located on the E. tereticornis map, and for SPR and STAB on the E. globulus map. We found different QTLs for MORT, ROOT, RCT, SPR and STAB. Putative QTLs accounted for 2.6–17.0% of the phenotypic variance of a trait (R2). Estimated standardized gene substitution effects varied between 0.13 and 0.49 phenotypic standard deviations (σp). These results indicate that the phenotypic variation in these traits has a meaningful genetic component and that stable QTLs can be found in a family of reasonable size where no previous knowledge of the trait was available.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 93 (1996), S. 1083-1089 
    ISSN: 1432-2242
    Schlagwort(e): Key words Dominant marker ; F2 family ; Linkage ; QTL ; Information function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Trans-dominant linked markers pairs (trans referring to the repulsion linkage phase) provide a model for inferring the F2 progeny genotype based upon both the conditional probabilities of F2 genotypes, given the F2 phenotype, and prior information on marker arrangement. Prior information of marker arrangement can be readily obtained from a linkage analysis performed on marker segregation data in a family resulting by crossing the F1 individual to a ``tester'' parent or else can be obtained directly from the gametes of the F1, or from recombinant inbred lines. We showed that a trans-dominant linked marker (TDLM) pair can be recoded as a ``co-dominant megalocus'' when the recombination fraction, r1, for a pair of TDLMs is less than 0.05. We obtained a maximum-likelihood estimator (MLE) of the recombination frequency, r2, between a TDLM pair and a co-dominant marker in an F2 family using the EM algorithm. The MLE was biased. Mean bias increased as r1 and r2 increased, and decreased as sample size increased. The information content for r2 was compared to the information content of dominant and co-dominant markers segregating in an F2 family. It was almost identical with two co-dominant markers when r1≤0.01 and r2≥0.05. For larger values of r1, (0.05≤r1≤0.15) a TDLM pair provided 75%–66% of the information content of two co-dominant markers. Although dominant markers can be converted to co-dominant markers by a laborious process of cloning, sequencing, and PCR, TDLM pairs could easily substitute for co-dominant markers in order to detect quantitative trait loci (QTLs) and estimate gene action in an F2 family.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    ISSN: 1432-2242
    Schlagwort(e): Key words Barley ; Yield ; Marker-assisted selection ; QTL ; QTL×E
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  We report results from a breeding strategy designed to accumulate favorable QTL alleles for grain yield identified in the SteptoeבMorex’ (SM) barley germplasm. Two map lines (SM73 and SM145) from the original mapping population were selected based on their marker genotype and QTL structure. When crossed, these lines would be expected to produce progeny with most favorable QTL alleles. One hundred doubled haploid (DH) lines from the F1 hybrid of this cross were genotyped with ten RFLP markers and one morphological marker defining grain yield to monitor QTL segregation. A subset of 24 lines representing various combinations of putatively favorable and unfavorable QTL alleles, together with Steptoe, ‘Morex’, SM73, and SM145, were phenotyped for grain yield in five environments. Multiple regression procedures were used to explore phenotype and genotype relationships. Most target QTLs showed significant effects. However, significance and magnitude of QTL effects and favorable QTL allele phase varied across environments. All target QTLs showed significant QTL-by-environment interaction (QTL×E), and the QTL on chromosome 2 expressed alternative favorable QTL alleles in different environments. Digenic epistatic effects were also detected between some QTL loci. For traits such as grain yield, marker-assisted selection efforts may be better targeted at determining optimum combinations of QTL alleles rather than pyramiding alleles detected in a reference mapping population.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-2242
    Schlagwort(e): QTL ; RFLP mapping ; marker-assisted selection ; Barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Quantitative trait locus (QTL) and QTL x environment (E) interaction effects for agronomic and malting quality traits were measured using a 123-point linkage map and multi-environment phenotype data from an F1-derived doubled haploid population of barley (Hordeum vulgare). The QTL × E interactions were due to differences in magnitude of QTL effects. Highly significant QTL effects were found for all traits at multiple sites in the genome. Yield QTL peaks and support intervals often coincided with plant height and lodging QTL peaks and support intervals. QTL were detected in the vicinity of a previously mapped Mendelian maturity locus and known function probes forα- andβ-amylase genes. The average map density (9.6 cM) should be adequate for molecular marker-assisted selection, particularly since there were few cases of alternative favorable alleles for different traits mapping to the same or adjacent intervals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 263 (2000), S. 375-387 
    ISSN: 1617-4623
    Schlagwort(e): Key words Cytokinesis ; Cytoplasmic dynein ; Septation ; Spindle pole body ; Aspergillus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The nudA1 mutation in the cytoplasmic dynein heavy chain gene inhibits nuclear migration, colony growth and asexual sporulation (conidiation) in the filamentous fungus Aspergillus nidulans. It also alters the location of the first cell division event (septation) and prevents nucleation of tip cells. We showed previously that a suppressor of nudA1, snaD290, partially reversed the nuclear migration defect and partially restored colony growth. We have now demonstrated that the snaD290 mutation also delays septation and restores the septum to its normal position, allowing tip cells to be nucleated. Although snaD290 does not affect nuclear migration or vegetative hyphal growth, it almost completely inhibits conidiation. We propose that the SNAD protein participates in septation, and is essential for asexual spore formation. SnaD encodes a novel 76-kDa coiled-coil protein (SNAD) that is located at the spindle pole body throughout the cell cycle. Therefore, our results suggest that proteins at the spindle pole body are likely to be involved in temporal regulation of septation in A. nidulans.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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