Comparison of protamines from freshwater and marine bivalve molluscs: Evolutionary implications

Abstract

We characterized for the first time a protamine from the spermatozoa of a freshwater bivalve, Dreissena polymorpha. We found that it contains a protamine very similar in composition to those found in marine bivalves. We concluded that freshwater does not impose any restriction on the composition of sperm basic proteins. We compared our results with those recently published by other authors and proposed an evolutionary pathway for bivalve sperm proteins as originating from histone H1. © 1987.