Posted by admin at 10:47 PM Tuesday, April 13, 2010
The race to fertilize an egg can be fierce. Millions of sperm cells compete against each other so as to pass on their genes to the next generation. Only one of them can be victorious. And yet, within this sexual battlefield, playing nice may be the best strategy for a male’s feisty swimmers. In a bizarre instance of cellular cooperation, sperm of polygamous deer mice (Peromyscus maniculatus) appear to team up to help each other swim faster. By aggregating, sperm can increase their swimming velocity, thereby out-competing single swimmers. Sperm mostly cooperate with their genetic relatives, and discriminate against non-relatives. However, this discrimination is absent in a closely-related monogamous species, which suggests that it arose as a result of competition among mates. Many males may mate with a single female in the polygamous species, so it will pay off for a sperm cell to cooperate with cells that came from the same male. The discovery was recently published in Nature (1) and shows that cooperation and discrimination among sperm relatives can evolve under highly competitive conditions. It seems that sex and love are not so different after all: loners always finish last.
Image by Gilberto Santa Rosa, Wikimedia Commons.