The evolutionary history of the sarafotoxin/endothelin/endothelin-like superfamily

The evolutionary relationships among 17 protein and nucleic acid sequences from the sarafotoxin/endothelin/endothelin-like superfamily of peptides were studied. The endothelin/endothelin-like gene family has diverged from an ancestral gene that has experienced an exon duplication event followed by two complete gene duplications. The sarafotoxin lineage diverged from the ancestral gene prior to the first gene duplication event. In several lineages, the peptides have independently accumulated identical amino acid replacements in position 2. This finding supports the hypothesis that residue 2 is crucial to biological activity.