New genes are added to most genomes on a steady basis. A new gene can either begin as a copy of an existing gene from elsewhere in the genome, or is created entirely ‘from scratch’ from a DNA sequence that had not previously encoded for a protein.
For reasons that are not fully understood, the total number of genes in most genomes remains fairly constant despite these regular additions. In their latest work, Palmieri et al. have investigated this paradox by following the evolutionary fate of orphan genes in a small group of related species of fruit fly.
New York Times columist Carl Zimmer writes about how this research adds to our understanding of where genes ultimately come from.