Genetic and lutionary mechanisms of convergent phenotypes in animals

Abstract

It is not uncommon that similar phenotypes independently evolved in species of evolutionarily distant lineages, known as convergent evolution. The occurrence of convergent phenotypes is widely believed to promote adaptations to the same or similar environments of evolutionarily distant species by increasing their fitness. More and more studies show that the similar or same genetic variations play key roles in origination and evolution of convergent phenotypes. As genomic data accumulating rapidly, some researchers systematically explored the relationships between convergent phenotypes and convergent genetic variations on a genome-wide scale, comprehensively revealed molecular bases in genetics and evolution of convergent phenotypes, and identified many genes undergoing convergent evolution that are closely related to convergent phenotypes. Nevertheless, it is difficult to verify strictly whether convergent variations at the molecular level are under Darwinian natural selection. Except for convergent variations satisfying functional convergence of the related genes, it is more important to demonstrate that molecular convergence indeed leads to occurrence of convergent phenotypes and significantly increases the fitness of the species undergoing convergent evolution.