Evolution and Differentiation of the Prion Protein Gene (PRNP) among Species

A total of 937 prion protein gene (PRNP) sequences belonging to 83 species in 56 genera of 26 families were analyzed in order to investigate its evolution and differentiation among species. The length of PRNP coding sequence for all species analyzed varied from 567 to 825 bp, which was mainly because of insertion or deletion in the repeat region within and among the species. TGA and TAG are the main stop codons in the PRNP gene. Bos taurus had the smallest variation in terms of average number of nucleotide differences (0.811), nucleotide diversity (0.0011), and nonsynonymous nucleotide diversity (0.0002) among all the ruminants. The reconstructed phylogenetic tree of PRNP of families and species was basically consistent with the taxonomy of National Center for Biotechnology Information except for Felidae (Felis catus), which was initially clustered with Moschidae rather than Mustelidae or Canidae.