Selection on different genes with equivalent functions: the convergence story told by Hox genes along the evolution of aquatic mammalian lineages

BMC Evolutionary Biology

Research Article

Brunno Borges¹  Tiana Kohlsdorf¹  Aline C. Dragalzew¹  Mariana F. Nery² 

[1] Departamento de Biologia, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil;Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil;

关键词: Cetaceans;    Pinnipeds;    Sirenians;    Molecular evolution;    Hox;    Positive selection;   

DOI  :  10.1186/s12862-016-0682-4

 received in 2016-02-12, accepted in 2016-05-10,  发布年份 2016

来源: Springer

【 摘 要 】

BackgroundConvergent evolution has been a challenging topic for decades, being cetaceans, pinnipeds and sirenians textbook examples of three independent origins of equivalent phenotypes. These mammalian lineages acquired similar anatomical features correlated to an aquatic life, and remarkably differ from their terrestrial counterparts. Whether their molecular evolutionary history also involved similar genetic mechanisms underlying such morphological convergence nevertheless remained unknown. To test for the existence of convergent molecular signatures, we studied the molecular evolution of Hox genes in these three aquatic mammalian lineages, comparing their patterns to terrestrial mammals. Hox genes are transcription factors that play a pivotal role in specifying embryonic regional identity of nearly any bilateral animal, and are recognized major agents for diversification of body plans.ResultsWe detected few signatures of positive selection on Hox genes across the three aquatic mammalian lineages and verified that purifying selection prevails in these sequences, as expected for pleiotropic genes. Genes found as being positively selected differ across the aquatic mammalian lineages, but we identified a substantial overlap of their developmental functions. Such pattern likely resides on the duplication history of Hox genes, which probably provided different possible evolutionary routes for achieving the same phenotypic solution.ConclusionsOur results indicate that convergence occurred at a functional level of Hox genes along three independent origins of aquatic mammals. This conclusion reinforces the idea that different changes in developmental genes may lead to similar phenotypes, probably due to the redundancy provided by the participation of Hox paralogous genes in several developmental functions.

【 授权许可】

CC BY   
© Nery et al. 2016