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THE TEGULA TANGO: A COEVOLUTIONARY DANCE OF INTERACTING, POSITIVELY SELECTED SPERM AND EGG PROTEINS
Author(s) -
Hellberg Michael E.,
Dennis Alice B.,
ArbourReily Patricia,
Aagaard Jan E.,
Swanson Willie J.
Publication year - 2012
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2011.01530.x
Subject(s) - biology , lysin , sperm , interspecific competition , gamete , evolutionary biology , vitelline membrane , sexual reproduction , genetics , zoology , ecology , gene , oocyte , embryo , escherichia coli , bacteriophage
Reproductive proteins commonly show signs of rapid divergence driven by positive selection. The mechanisms driving these changes have remained ambiguous in part because interacting male and female proteins have rarely been examined. We isolate an egg protein the vitelline envelope receptor for lysin (VERL) from Tegula , a genus of free‐spawning marine snails. Like VERL from abalone, Tegula VERL is a major component of the VE surrounding the egg, includes a conserved zona pellucida (ZP) domain at its C‐terminus, and possesses a unique, negatively charged domain of about 150 amino acids implicated in interactions with the positively charged lysin. Unlike for abalone VERL, where this unique VERL domain occurs in a tandem array of 22 repeats, Tegula VERL has just one such domain. Interspecific comparisons show that both lysin and the VERL domain diverge via positive selection, whereas the ZP domain evolves neutrally. Rates of nonsynonymous substitution are correlated between lysin and the VERL domain, consistent with sexual antagonism, although lineage‐specific effects, perhaps owing to different ecologies, may alter the relative evolutionary rates of sperm‐ and egg‐borne proteins.