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USING COMPARATIVE GENOMIC DATA TO TEST FOR FAST‐X EVOLUTION
Author(s) -
Counterman Brian A.,
ORTíZBarrientos Daniel,
Noor Mohamed A. F.
Publication year - 2004
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2004.tb01688.x
Subject(s) - biology , nonsynonymous substitution , drosophila pseudoobscura , genetics , evolutionary biology , gene , chromosome , molecular evolution , autosome , x chromosome , sterility , genome
Genes may acquire nonsynonymous substitutions more rapidly when X‐linked than when autosomal, but evidence for “fast‐X evolution” has been elusive. Fast‐X evolution could explain the disproportionate contribution of X‐linked genes to hybrid sterility and other traits. Here, we use a comparative genomic approach, with sequences of 30‐‐110 genes in four Drosophila species, to test for fast‐X evolution. Specifically, the 3L autosome arm in D. melanogaster and D. simulans is homologous to the right arm of the X chromosome in D. pseudoobscura and D. miranda . We executed two paired comparisons to determine how often genes on this chromosome arm exhibit higher rates of nonsynonymous substitution in the D. pseudoobscura species group, as predicted by fast‐X evolution. We found a statistically significant pattern consistent with fast‐X evolution in one comparison and a similar trend in the other comparison. Variation in functional constraints across genes may have masked the signature of fast‐X evolution in some previous studies, and we conclude paired comparisons are more powerful for examining rates of evolution of genes when X‐linked over autosomal.