New genes as drivers of phenotypic evolution.

TLDR: This work has shown that new genes, despite being present in the genomes of only a subset of species, can rapidly evolve indispensable roles in fundamental biological processes, including development, reproduction, brain function and behaviour.

Abstract: Genes that have originated in recent evolution are present in only a subset of organisms and are often assumed to be dispensable or redundant. This Review discusses our latest understanding of how new genes in diverse species have actually evolved to have important functions in diverse developmental and physiological processes in various organisms. During the course of evolution, genomes acquire novel genetic elements as sources of functional and phenotypic diversity, including new genes that originated in recent evolution. In the past few years, substantial progress has been made in understanding the evolution and phenotypic effects of new genes. In particular, an emerging picture is that new genes, despite being present in the genomes of only a subset of species, can rapidly evolve indispensable roles in fundamental biological processes, including development, reproduction, brain function and behaviour. The molecular underpinnings of how new genes can develop these roles are starting to be characterized. These recent discoveries yield fresh insights into our broad understanding of biological diversity at refined resolution.