Concerted evolution and higher-order repeat structure of the 1.709 (satellite IV) family in bovids

Abstract

The 1.709 or satellite IV repeated DNA family originally isolated from the domestic cow was analyzed using Southern blotting, pulsed field gel electrophoresis, fluorescence in situ hybridization, and DNA sequencing in species belonging to the genera Bos, Bison, Bubalus, Syncerus, Boselaphus, and Tragelaphus. Hybridization indicates that the family has been amplified in Bos, Bison, Bubalus, and Syncerus but not in Boselaphus or Tragelaphus. Pericentromeric, higher-order repeat substructure exists in all species, with multimeric arrays ranging in size from 10 to 1500 kb. Sequence analysis of a 492-bp PCR product revealed comparable levels (0.2-4.5%) of intra- and interspecific divergence when species of Bos and Bison were compared, supporting the idea that species of these two genera should be recognized under the genus Bos. Alternatively, all Syncerus sequences cluster as a monophyletic group on an evolutionary tree and differ from those of Bos/ Bison by about 13%. Comparing these findings with the fossil record indicates that concerted evolution has occurred since Bos/ Bison and Syncerus last shared a common ancestor (5.0 MYA) but before the radiation of the genus Bos (2.5 MYA): GenBank accession numbers AY517856-AY517904.