Evolution of a complex phenotype with biphasic ontogeny: Contribution of development versus function and climatic variation to skull modularity in toads

Autor(es)

Simon, Monique Nouailhetas ^[1] ; Marroig, Gabriel ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Genet & Biol Evolut, Inst Biociencias, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ECOLOGY AND EVOLUTION; v. 7, n. 24, p. 10752-10769, DEC 2017.
• Citações Web of Science: 6

Resumo

The theory of morphological integration and modularity predicts that if functional correlations among traits are relevant to mean population fitness, the genetic basis of development will be molded by stabilizing selection to match functional patterns. Yet, how much functional interactions actually shape the fitness landscape is still an open question. We used the anuran skull as a model of a complex phenotype for which we can separate developmental and functional modularity. We hypothesized that functional modularity associated to functional demands of the adult skull would overcome developmental modularity associated to bone origin at the larval phase because metamorphosis would erase the developmental signal. We tested this hypothesis in toad species of the Rhinella granulosa complex using species phenotypic correlation pattern (P-matrices). Given that the toad species are distributed in very distinct habitats and the skull has important functions related to climatic conditions, we also hypothesized that differences in skull trait covariance pattern are associated to differences in climatic variables among species. Functional and hormonal-regulated modules are more conspicuous than developmental modules only when size variation is retained on species P-matrices. Without size variation, there is a clear modularity signal of developmental units, but most species have the functional model as the best supported by empirical data without allometric size variation. Closely related toad species have more similar climatic niches and P-matrices than distantly related species, suggesting phylogenetic niche conservatism. We infer that the modularity signal due to embryonic origin of bones, which happens early in ontogeny, is blurred by the process of growth that occurs later in ontogeny. We suggest that the species differing in the preferred modularity model have different demands on the orbital functional unit and that species contrasting in climate are subjected to divergent patterns of natural selection associated to neurocranial allometry and T3 hormone regulation. (AU)

• Processo FAPESP: 11/07584-2 - Integração morfológica e modularidade em crânios das espécies do grupo Rhinella granulosa (Lissamphibia: Anura: Bufonidae)
• Beneficiário: Monique Nouailhetas Simon
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/14295-7 - Modularidade e suas consequências evolutivas
• Beneficiário: Gabriel Henrique Marroig Zambonato
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 09/54203-4 - EMU: infra-estrutura para análises de metabolismo, biologia molecular e celular em projetos de genômica funcional e comparativa
• Beneficiário: Gabriel Henrique Marroig Zambonato
• Linha de fomento: Auxílio à Pesquisa - Programa Equipamentos Multiusuários