Amplification of telomeric DNA and the extent of karyotypic evolution.
The distribution of telomeric DNA in the genomes of the antelope ground squirrel, Ammospermophilus harrisii (family Sciuridae; 2n = 32) and the African black-footed cat, Felis nigripes (family Felidae; 2n = 38) were compared by fluorescence in situ hybridization (FISH) technique. These two mammalian species have the highest and the lowest amount of C-banded regions, respectively. FISH preparations with the human telomeric DNA probe showed that all C-banded segments in the A. harrisii chromosomes, except a few intercalary segments, were hybridizing with this DNA. F. nigripes showed hybridization only on the termini of each chromosome, and the C-banded regions did not hybridize with telomeric DNA on FISH analysis. The C-banded chromosomal arms in another rodent species, Peromyscus eremicus (family Cricetidae; 2n = 48), when hybridized with human telomeric DNA showed signals only in the termini of chromosomes but not in the heterochromatic arms. These observations indicate that not all C-banded regions in rodent species are telomeric DNA. The amplification of telomeric DNA in relation to speciation is discussed.
Department of Cell Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
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Pathak
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Dolhonde
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Multani
D000818:Animals; D002503:Centromere / Q000737:chemistry; D002871:Chromosome Banding; D004247:DNA / Q000235:genetics*; D019143:Evolution, Molecular; D005784:Gene Amplification; D006570:Heterochromatin / Q000502:physiology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008322:Mammals / Q000235:genetics*; D012377:Rodentia / Q000235:genetics; D013045:Species Specificity; D016615:Telomere / Q000737:chemistry*
D006570:Heterochromatin; D004247:DNA