De novo gene birth is emerging as an important mechanism for the formation of new genes, but how de novo genes evolve and which is their impact in the functional proteome, are still poorly understood questions. In contrast to genes formed by duplication and subsequent divergence, de novo genes arise from non-genic parts of the genome, which become transcribed and translated. We have used comparative transcriptomics data from 11 different yeast species, together with ribosome profiling data from Saccharomyces cerevisiae, to obtain a comprehensive view of the genes that have recently been born de novo in the species.
The study has identified 213 transcripts that have emerged de novo in the past few Million years, nearly half of which encode proteins. We have discovered that these transcripts often overlap other genes in the opposite orientation, unveiling novel ways in which the coding capacity of a compact genome can be increased during evolution. We have also obtained evidence that a subset of de novo proteins are likely to represent recent adaptations to stress conditions. The work advances our understanding on de novo genes and helps establish S. cerevisiae and closely related species as a model system to study this intriguing evolutionary process.
