Fig. 3From: The evolutionary process of mammalian sex determination genes focusing on marsupial SRYsInferred ancestral substitutions are shown on the tree by parsimony. Four substitutions were specific to the branch that SRY differentiated from SOX3 in the ancestor of Theria. 13 substitutions were on the branch containing the eutherian SRY, and seven substitutions were on the branch containing the marsupial SRY. The divergence time on the tree, 79 or 105 MYA coincides with the radiation of marsupials or eutherians, and 210–180 MYA is the divergence time of monotremes and TheriaBack to article page