New Peptides Under the s(ORF)ace of the Genome

Hundreds, perhaps thousands of previously unidentified functional small peptides could exist in most genomes, but these sequences have been generally overlooked. The discovery of genes encoding small peptides with important functions in different organisms has ignited the interest in these sequences and led to an increasing amount of effort towards their identification. Here, we review the advances, both computational and biochemical, that are leading the way in the discovery of putatively functional small open reading frame genes (smORFs), as well as the functional studies that have been carried out as a consequence of these searches. The evidence suggests that smORFs form a substantial part of our genomes, and that their encoded peptides could have a variety of important cellular functions.