Fig. 3From: Convergent degeneration of olfactory receptor gene repertoires in marine mammalsExpansion of the OR gene in mammals. a and b NJ phylogenetic trees constructed from all intact OR genes in OGG2–1 and OGG2–2, respectively. c and d Number of gene amplifications and losses in the OGGs of (a) and (b) in different branches and nodes, respectivelyBack to article page