Evolution by gene loss

Abstract

The recent increase in genomic data is revealing an unexpected perspective of gene loss as a pervasive source of genetic variation that can cause adaptive phenotypic diversity. This novel perspective of gene loss is raising new fundamental questions: How relevant has gene loss been in the divergence of phyla? How do genes change from being essential, to dispensable, to lost? Is gene loss mostly neutral, or can it be an effective way of adaptation? This Review addresses these questions and also discusses insights from genomic studies of gene loss in populations and their relevance in evolutionary biology and biomedicine.