The idea of sperm racing furiously towards the egg – survival of the fastest if you like, is cemented into popular culture thanks to a certain Woody Allen movie. The most vigorous and energetic sperm stand the best chance of becoming an embryo – or so we thought. Sneaky Sperminators.
Researchers from Berlin have recently discovered that sperm cells have an additional method of winning the race, and it looks like some of them can cheat! Not only can they swim their way to the front of the queue fair and square, but they’re also able to disable and eliminate the competition by nefarious means.
Each sperm cell carries a unique set of data, which helps to make every person a one-off individual (excluding identical twins). The wrigglers that are less healthy or well-formed tend to fall behind and lose the race more often. This is thought to ensure that the resulting embryo, with its random mix of both mum and dad’s genetic material, is as genetically healthy as possible.
A DNA segment that occurs in some mammal sperm cells, helps to make them swim faster than those without it. But scientists also discovered that this type of sperm can actually poison and wipe out other sperm on the same journey.
The sperm with a genetic factor called T-haplotype are able to poison all of the sperm around them, and in doing so they poison themselves too. While this might seem counterintuitive, the crafty T-sperm have a trick up their sleeve. They also produce the antidote to this poison, which only works on T-sperm. Sneaky!
Although T-sperm doesn’t really stand for Thanos sperm, the famous ending to the Marvel movie is a handy way to visualise what is happening on a microscopic scale.
Our understanding of this discovery is limited to small mammals at the moment. However, researchers speculate that the dirty tricks our genes sometimes pull in order to get themselves passed on may help scientists to understand some types of infertility in men in the future.