IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| King, V.; Goodfellow, P.N.; Pearks Wilkerson, A.J.; Johnson, W.E.; O'Brien, S.J.; Pecon-Slattery, J. | |
| Evolution of the male-determining gene SRY within the Cat Family Felidae | |
| 2007 Genetics (175): 1855-1867 | |
In most placental mammals, SRY is a single-copy gene located on the Y chromosome and is the trigger for male sex determination during embryonic development. Here, we present comparative genomic analyses of SRY (705 bp) along with the adjacent noncoding 59 flank (997 bp) and 39 flank (948 bp) in 36 species of the cat family Felidae. Phylogenetic analyses indicate that the noncodinggenomic flanks and SRY closely track species divergence. However, several inconsistencies are observed in SRY. Overall, the gene exhibits purifying selection to maintain function (v = 0.815) yet SRY is under positive selection in two of the eight felid lineages. SRY has low numbers of nucleotide substitutions, yet most encode amino acid changes between species, and four different species have significantly altered SRY due to insertion/ deletions. Moreover, fixation of nonsynonymous substitutions between sister taxa is not consistent and may occur rapidly, as in the case of domestic cat, or not at all over long periods of time, as observed within the Panthera lineage. The former resembles positive selection during speciation, and the latter purifying selection to maintain function. Thus, SRY evolution in cats likely reflects the different phylogeographic histories, selection pressures, and patterns of speciation in modern felids. |
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