Evolutionary relationships among the bovine PAG genes represented in the bovine genome build 3.1. The tree was created from the inferred amino acid sequences by using the Minimal evolution method in the MEGA 4.0 program. The tree was drawn to scale, and the percentage representations obtained from the bootstrap analysis were shown next to the appropriate branch point. Notice the clear separation of the PAG gene family into two groups, the modern and the ancient PAGs. Also notice the relatively shorter branch lengths in the modern PAG clusters compared to the ancient PAGs.
Telugu et al. BMC Genomics 2009 10:185 doi:10.1186/1471-2164-10-185