Abstract: In order to analyze SRY gene polymorphisms and patrilineal phylogenetic relationships for Bos grunniens and other Bos species, SRY gene were amplified and cloned from genomic DNA of five Maiwa yaks, and SRY gene sequences of other Bos species and Bison bonasus were retrieved from GenBank. Polymorphism analyses were performed to examine the variations of SRY gene and the sequences encoding HMG-box among Bos species. The phylogenetic tree and Median-Joining network of Bos species were constructed based on SRY gene sequences, exhibiting the patrilineal phylogenetic relationships for Bos species. The nonsynonymous mutation rate of gene sequences encoding N and C terminals of SRY (flanking HMG-box) (0.57) was significantly lower than that encoding HMG-box (0.69).We deduced that positive selection might have imposed both on gene sequences encoding HMG-box and their flanking regions. Compared with Bubalus bubalis and Bos grunniens, Bison bonasus were more closely related to Bos taurus, which supported the view from a pateilineal aspect that extant cattle species originated from extinct auroch and Bos primigenius. Bos grunnies might have two or more patrilineal origins. Syncerus caffer and Bubalus bubalis showed distinct variations in SRY gene which led to divergent evolution, and phylogenetic analyses supported the sub-species classification of these buffaloes. Therefore, Bos species exhibited specific variation features in SRY gene and the patrilineal phylogenetic analysis supported the viewpoints from previous studies.

Key words:

Bos grunniens; Bos species; SRY gene; features of variations; patrilineal phylogenetic relationships