Figure 1

Phylogenetic tree and exon-intron structure of hatching enzyme genes. The ML tree was constructed from nucleotide sequences of mature enzyme portions of teleostean hatching enzyme genes using osteoglossiform gene (AwHE) as an outgroup. Numbers at the nodes show bootstrap support values, and the values under 50% are removed. Exon-intron structures are shown at the right of gene names. The intron numbers corresponding to the assumed ancestral hatching enzyme gene are shown at the top. The numbers in boxes represent intron phases, and the boxes are colored black for conserved introns, white for lost introns, and gray for inserted introns or introns having intron phase different from that of the ancestral gene.