Phylogenetic tree of GDF9 proteins. The phylogenetic tree was built from protein sequences using the Ensembl database. The tree is the fusion on the NJ topology, of three phylogenetic trees built based on neighbour joining, maximum parsimony, and maximum likelihood. For each node, bootstrap values are reported for each npl method. An asterisk indicates that the bootstrap value is lower than 50%. Bootstrapping was carried out with 1000 replications. "R" node represents the ancestral gene. For clarity reasons, some of the branches corresponding to paralogous genes or orthologous genes in higher vertebrates were reduced and indicated by a circled C.