Molecular Biology and Evolution, Vol 10, 647-659, Copyright © 1993 by Society for Molecular Biology and Evolution
L Bachmann and D Sperlich
The highly repetitive satellite DNA family "ATOC180" is specific for the
three closely related species Drosophila obscura, D. ambigua, and D.
tristis but does not occur in their closest relatives D. subsilvestris and
D. bifasciata. Approximately 10,000 copies/haploid genome of approximately
180-bp repetition units are tandemly arranged in the centromeric
heterochromatin of all chromosomes of all three species. Molecular analysis
of 29 cloned repeats shows much intra- and interspecific sequence
homogeneity. Single nucleotide changes are the main source of variability
and distinguish the sequence-, subfamily- and species-specific ATOC180
repeats from each other. Based on these nucleotide differences,
phylogenetic dendrograms were constructed and compared with published trees
for other traits. The data indicate that the sequences of the ATOC180
satellite DNA family probably arose in a phylogenetically "short period"
during the anagenetic evolution of the common ancestor of D. obscura, D.
tristis, and D. ambigua, as a consequence of a process of genome
reorganization, followed by a "long period" of entirely gradual sequence
evolution. For the latter period, an evolutionary rate of 3 x 10(-8)
substitutions/site/year was calculated.
ORIGINAL ARTICLE
Gradual evolution of a specific satellite DNA family in Drosophila ambigua, D. tristis, and D. obscura
Department of Population Genetics, University of Tubingen, Germany.
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