Tsubouchi Ayako, Fukui Daisuke, Ueda Miya, Tada Kazumi, Toyoshima Shouji, Takami Kazutoshi, Tsujimoto Tsunenori, Uraguchi Kohji, Raichev Evgeniy, Kaneko Yayoi, Tsunoda Hiroshi, Masuda Ryuichi
Department of Natural History Sciences, Hokkaido University, Sapporo, Japan.
Zoolog Sci. 2012 Mar;29(3):151-61. doi: 10.2108/zsj.29.151.
To investigate the molecular phylogeny and evolution of the family Canidae, nucleotide sequences of the zinc-finger-protein gene on the Y chromosome (ZFY, 924-1146 bp) and its homologous gene on the X chromosome (ZFX, 834-839 bp) for twelve canid species were determined. The phylogenetic relationships among species reconstructed by the paternal ZFY sequences closely agreed with those by mtDNA and autosomal DNA trees in previous reports, and strongly supported the phylogenetic affinity between the wolf-like canids clade and the South American canids clade. However, the branching order of some species differed between phylogenies of ZFY and ZFX genes: Cuon alpinus and Canis mesomelas were included in the wolf-like canid clades in the ZFY tree, whereas both species were clustered in a group of Chrysocyon brachyurus and Speothos venaticus in the ZFX tree. The topology difference between ZFY and ZFX trees may have resulted from the two-times higher substitution rate of the former than the latter, which was clarified in the present study. In addition, two types of transposable element sequence (SINE-I and SINE-II) were found to occur in the ZFY final intron of the twelve canid species examined. Because the SINE-I sequences were shared by all the species, they may have been inserted into the ZFY of the common ancestor before species radiation in Canidae. By contract, SINE-II found in only Canis aureus could have been inserted into ZFY independently after the speciation. The molecular diversity of SINE sequences of Canidae reflects evolutionary history of the species radiation.
为了研究犬科动物的分子系统发育和进化，测定了12种犬科动物Y染色体上锌指蛋白基因（ZFY，924 - 1146 bp）及其X染色体上同源基因（ZFX，834 - 839 bp）的核苷酸序列。由父系ZFY序列重建的物种间系统发育关系与先前报道中基于线粒体DNA和常染色体DNA构建的系统发育关系高度一致，并有力地支持了狼样犬科动物分支与南美犬科动物分支之间的系统发育亲缘关系。然而，ZFY和ZFX基因的系统发育树中某些物种的分支顺序不同：豺和黑背胡狼在ZFY树中被归入狼样犬科动物分支，而在ZFX树中这两个物种与鬃狼和薮犬聚为一组。ZFY和ZFX树之间的拓扑结构差异可能是由于前者的替换率比后者高两倍，本研究对此进行了阐明。此外，在所检测的12种犬科动物的ZFY最后一个内含子中发现了两种转座元件序列（SINE - I和SINE - II）。由于所有物种都共享SINE - I序列，它们可能在犬科动物物种辐射之前就已插入共同祖先的ZFY中。相比之下，仅在金豺中发现的SINE - II可能在物种形成后独立插入到ZFY中。犬科动物SINE序列的分子多样性反映了物种辐射的进化历史。
