CONCERTED EVOLUTION IN AN EGG RECEPTOR FOR A RAPIDLY EVOLVING ABALONESPERM PROTEIN

Gamete interactions during fertilization exhibit species specificity. In abalone, the sperm protein Lysin species-specifically creates a hol e in the egg envelope. Lysin evolves rapidly by positive Darwinian sel ection. Evolution of the egg receptor for Lysin provides the selective pressure for Lysin's divergence. The egg receptor for lysin is a tand emly repeated sequence that evolves by concerted evolution. Concerted evolution in the egg receptor could explain the rapid, adaptive evolut ion in sperm Lysin and may provide an underlying molecular mechanism t hat gives rise to species-specific fertilization.