BioProject

New genes are those that originated relatively recently and are only present in a subset of species in a phylogeny. More...

New genes are those that originated relatively recently and are only present in a subset of species in a phylogeny. Evidence from humans and other species has demonstrated that, despite their young age, new genes can exhibit novel functions that are essential for the survival of an organism. One potential mechanism by which new genes gain essential functions is through the acquisition of many new interactions with pre-existing genes. This hypothesis is consistent with well-established observations that genes with many interaction partners are more likely to have essential functions. However, the accumulation of gene-gene interactions is, on average, a slow evolutionary process. This raises the question of how, in a short evolutionary time, new genes can acquire multiple novel interactions and how this might lead to their essential roles in the survival of an organism. In this study, we characterized the evolutionary history and function of a young duplicated gene that quickly became essential for the survival of Drosophila melanogaster. This young gene (CG7804) duplicated from another essential gene (TBPH) through retrotransposition less than four million years ago (Zhang et al. 2010), and is present in few Drosophila species. We found that unlike its evolutionarily conserved, broadly expressed parental gene, CG7804 has evolved rapidly under positive selection since its birth. Despite its young age, functional analyses show that CG7804 is essential for the survival of D. melanogaster. In particular, its expression is essential at different tissues from its parental gene. RNA-seq and ChIP-seq analysis suggests that CG7804 acquired essential function to survival through gaining new DNA binding targets that influence the expression of a suite of genes with other essential function and large number of protein-protein interaction. Our study is an important step towards deciphering the evolutionary trajectory by which duplicated genes functionally diverge from the parental gene and become essential. Overall design: RNAseq of wildtypes and CRISPR-knock out mutant of CG7804 Less...