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  • 1
    Electronic Resource
    Electronic Resource
    Evolution of zinc finger-Y and zinc finger-X genes in oryzomyne-akodontine rodents (Cricetidae) (1992)
    Springer
    Journal of molecular evolution 34 (1992), S. 54-61 
    Details
    ISSN: 1432-1432
    Keywords: Zfy-Zfx genes ; Gene evolution ; Oryzomyne-akodontine rodents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Zinc finger-Y (Zfy) and zinc finger-X (Zfx) genes were analyzed by Southern blotting in male and female specimens of 10 species belonging to the oryzomyne-akodontine stock of Cricetidae rodents. DNA fragments were used as characters to construct a parsimony tree of the genes. Zfx and Zfy trees in general coincide with the evolutionary history of the taxa. Both trees show Oryzomys longicaudatus genes as the outgroup whereas Akodon xanthorrhinus genes are also distant from those of the other species. Oxymycterus rufus and Bolomys obscurus share related sequences, while genes from the other six Akodon species form a group of their own. It was found that 9 out of the 10 species analyzed show Zfy amplification in a range varying from 2 to 24 copies and with a pattern that is clade specific. The estimation of the average changes per character strongly suggests that Zfy has evolved more rapidly than Zfx; our estimates of the rate of nucleotide substitution are 4.6 times higher for Zfy than for Zfx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163852
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  • 2
    Electronic Resource
    Electronic Resource
    Complement with 38 chromosomes in two south American populations ofRattus rattus (1969)
    Springer
    Cellular and molecular life sciences 25 (1969), S. 1111-1112 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Resumen Se estudiaron los cromosomas de 16 ejemplares deRattus rattus provenientes de la Provincia de Buenos Aires (Argentina) y del Estado de Rio Grande do Sul (Brasil). En todos los animales el complemento estuvo formado por 38 cromosomas. Considerando que en las ratas el complemento de 42 cromosomas es probablemente el mas generalizado, se sugiere que el complemento de 38 cromosomas ha derivado del de 42 mediante un proceso de reordenamiento cromosómico con fusión céntrica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01901465
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Restriction site patterns in the ribosomal DNA of Camelidae (1994)
    Springer
    Genetica 92 (1994), S. 115-122 
    Details
    ISSN: 1573-6857
    Keywords: camelids ; ribosomal DNA ; restriction map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The restriction map of rDNA from South American camelids and the Bactrian camel was analyzed by digestion of high-molecular-weight DNA with endonucleases EcoRI, BamHI and the two combined followed by Southern blot hybridization with probes for the 18S and 28S rDNA sequences. We scored a total of 17 restriction sites, six of which were mapped conserved in all the species. The other eleven corresponded to spacer regions and revealed variations between these taxa. The study showed that the two groups differ in the length of the internal transcribed spacer. Also they showed the existence of two regions of fast evolution on the opposite termini of the external spacer. A restriction site present at low frequency in the non-transcribed spacer of guanaco and llama was the only difference encountered within the South American group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00163760
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  • 4
    Electronic Resource
    Electronic Resource
    DNA composition in South American camelids I. Characterization and in situ hybridization of satellite DNA fractions (1987)
    Springer
    Genetica 72 (1987), S. 137-146 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The DNA composition and the in situ hybridization of satellite fractions were analysed in the New World camelids llama, alpaca, guanaco and vicuña. In the four camelid forms, it was possible to identify a similar main band DNA and five satellite fractions (I–V) with G+C base contents ranging from 32% to 66%. Satellites II–V from llama were in situ reannealed on chromosomes from the four camelid forms. The results obtained were: (a) the four satellites hybridized with regions of C-banding (centromeric regions of all chromosomes and short arms of some autosomes); (b) in general, homologous hybridizations (llama DNA versus llama chromosomes) were more efficient than heterologous reassociations; there were however three exceptions to this rule (vicuña and alpaca satellite fraction II, chromosome group B; vicuña fraction V, chromosome groups A and B); (c) X chromosomes from the four camelids had satellites III–V but lacked satellite II, (d) no satellite fraction was detected on chromosome Y. The analysis of the in situ hybridization patterns allowed to conclude that most or all C-banded chromosome regions comprise several satellite DNA fractions. It is, moreover, proposed that there is an ample interspecies variation in the number of chromosomes that cross-react with a given satellite fraction. Our data give further support to the close genomic kinship of New World camelids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00123172
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  • 5
    Electronic Resource
    Electronic Resource
    DNA of Akodon (Rodentia, Cricetidae). I. Biophysical characterization (1979)
    Springer
    Biochemical genetics 17 (1979), S. 297-303 
    Details
    ISSN: 1573-4927
    Keywords: Akodon ; Cricetidae ; DNA characterization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Buoyant density in CsCl, melting temperature, and G + C base content of the DNA from four species of Akodon (Rodentia, Cricetidae) were determined. The buoyant density values of 1.699–1.701 g/cm3 were in accordance with the data reported for other cricetids. No satellite bands were seen in neutral CsCl. The T m values determined in 1 × SSC ranged from 86.2 to 87.0 C, which corresponds to G + C contents of 41.2–43.2%. There was good agreement in DNA base composition of the four species, although values were slightly higher in A. obscurus, suggesting a certain degree of interspecies variability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498970
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  • 6
    Electronic Resource
    Electronic Resource
    Ag-NOR staining and in situ hybridization of rDNA in the chromosomes of the South American camelids (1989)
    Springer
    Genetica 79 (1989), S. 215-222 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The location and frequency of Ag-stained NORs and sites of rDNA hybridization were studied in the chromosomes of the South American camelids. In the four camelids these regions occur distally on chromosomes 18, 21, and 27 and the smallest biarmed elements. Quantitative analysis of NOR distribution showed variations between both cells and species. In llama, guanaco and alpaca the NORs number averaged 6 per cell, this being higher than in vicuña where the average was 3. Relative frequencies of NOR-bearing chromosomes in the four camelids were similar. Yet, in vicuña the virtual absence of NOR sites on one of the smallest biarmed pairs was observed. The rDNA sites assessed in llama and vicuña by in situ hybridization with cloned 18S DNA were coincident with the NOR locations and with the frequencies characteristics for each species. Moreover, varying the exposure time of the autoradiographs, labeling patterns specific for each camelid were observed. Grain counts on individual chromosomes indicated that under our conditions one month exposure is enough to demonstrate all the rDNA sites available in the complement of llama. Conversely, at least two months are necessary to show the total sites existing in vicuña. Most probably this finding reflects the presence of variations in the amount of copies of the ribosomal genes per chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121515
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