Phylogenetic tree of high glycine-tyrosine KRTAP genes of all mammals. Simplified phylogeny of all of the high glycine-tyrosine KRTAP genes generated by the neighbor-joining algorithm using p-distances. Genes of each subfamily are represented by different colors. Numbers on branches are the reliabilities of the branches which are calculated by interior branch tests with 1,000 replications. The bars indicate six subfamilies (6, 7, 8, 19, 20 and 21) of HGT-KRTAP genes.