Characterization and evolutionary relevance of the sperm nuclear basic proteins from stickleback fish

We have characterized the sperm nuclear basic proteins (SNBPs) of the stick lebacks in the suborder Gasterosteoidei. The complete amino acid sequence o f the protamines from Aulorhynchus flavidus, Pungitius pungitius, Gasterost eus aculeatus, (anadromous) and G. wheatlandi, as well as the sequences of the protamines of several species pairs of freshwater G. aculeatus, have be en determined. Analysis of the primary structure of these proteins has show n that: a) despite the relatively low amino acid complexity and small molec ular mass of these basic proteins, they are very good molecular markers at the generic level. The bootstrap parsimony analysis using their sequences p rovides a phylogenetic relationship for the old anadromous species of Gaste rosteoidei which is identical to that obtained from morphological and behav ioral analysis; b) the comparison of the sequences also suggests that prota mines from the suborder Gasterosteoidei have most likely evolved from a com mon gene in the early Acanthoptetygii by an extension of the carboxy termin al portion of the molecule; c) protamines a re not good markers for recent postglacial freshwater isolates of G. aculeatus. However, in the unique cas e of Enos Lake (British Columbia), we have been able to detect an additiona l minor protamine component in the benthic forms of G. aculeatus that is no t present in the limnetic forms. Thus, this new protamine must have appeare d during the past 12,000 years concomitantly with the speciation of benthic s and limnetics in this lake. Mol. Reprod. Dev. 57:185-193, 2000. (C) 2000 Wiley-Liss, Inc.