Figure 5From: Multiple gains of spliceosomal introns in a superfamily of vertebrate protease inhibitor genesPhylogenetic tree of vertebrates emphasizing timescale and lineages displaying intron gain in serpin genes. The estimated divergence times (in mya), taken from ref. [40], are marked with blue arrows. The time interval of intron gains in ray-finned fishes is indicated (red arrow).Back to article page