Playing dirty: Sperm caught poisoning competitors to reach the egg first

Geneticists from the Max Planck Institute for Molecular Genetics, in Berlin, have discovered a genetic variant in mice that allows sperm cells to poison their competitors before the race to the egg has even begun.

The poisoning occurs while the individual sperm cells are in development and before they step up to the ‘starting line,’ so to speak, preventing them from accurately navigating their way to the egg. 

“Imagine a marathon in which all the participants get poisoned drinking water, but some runners also take an antidote,” says institute director Bernhard Herrmann.

However, the researchers also found there could be instances where the would-be assassins, whom Hermann dubs “ruthless competitors,” overdosed on their own poison if they killed too many pretenders to the throne. 

The research focuses on a particular protein switch called RAC1 that is crucial to allow sperm to navigate successfully during their quite literal life or death race. If this is interfered with in any way, their internal guidance system fails, as do their hopes of reaching the egg, and life itself.

Genetic research such as this, regardless of the animal involved, can yield insights into and improve humanity’s understanding of the wider process of evolution across all species, particularly the miserly means by which certain genetic variants gain an unfair advantage in the race for life.

Think your friends would be interested? Share this story!