Biological process

sperm activation

A process required for sperm to reach fertilization competence. Sperm undergo an incompletely understood series of morphological and molecular maturational processes, termed capacitation, involving, among other processes, protein tyrosine phosphorylation and increased intracellular calcium.

Avian spermatozoa do not require a period of capacitation, since they are competent to fertilize the egg without a prolonged sojourn in the oviduct or in a capacitation medium in vitro. Therefore, sperm capacitation can only be applied to Aves to refer to gene products involved in processes that occur prior to sperm being deposited from the avian male. The term cannot apply to processes occurring in the avian female reproductive tract.