How the fly selects its reproductive male

A team has discovered an RNA coding for a micro-peptide – a very small protein – that plays a crucial role in the competition between spermatozoa from different males of the Drosophila with which the female mates. In addition to shedding new light on this biological mechanism, this work highlights the importance of small peptides, a class of proteins that is now emerging as a key player in complex biological processes.