The evolution of new genes often goes hand in hand with the emergence of novel traits in species as they evolve. One of the great riddles in evolutionary biology has therefore always been how genetic novelty arises. The old theory was that new genes had to come from somewhere but this new research shows that some orphan genes come strictly from junk genes. But in the past 15 years, evidence for de novo genes has steadily accumulated, so much so that the debate has shifted from whether de novo genes exist to how much they contribute to evolution and adaptation.
- Cells’ fitness generally depends on the smooth functioning of networks of genes that have coevolved to work together.
- Most of the genes in every species can also be found in at least one other species.
- Some genes did not seem to belong to any family. These “orphan genes” appeared specifically in certain lineages and had no obvious ancestors or cousins.
“Genes derived from other genes have a better chance of blending into those networks.”