Predictors for reproductive isolation in a ring species complex following genetic and ecological divergence

BMC Evolutionary Biology

William B Monahan¹  David B Wake²  Ricardo J Pereira³ 

[1] CIBIO, Centro de Investigao em Biodiversidade e Recursos Genticos, Universidade do Porto, Campus Agrrio de Vairo, Vairo, Portugal;Departamento de Biologia, Faculdade de Cincias da Universidade do Porto, Porto, Portugal;Museum of Vertebrate Zoology and Department of Integrative Biology, 3101 Valley Life Sciences Building, University of California, Berkeley, USA

关键词: Reproductive Isolation;    Genetic Interaction;    Color Pattern;    Hybrid Zone;    Ecological Divergence;   

DOI  :  10.1186/1471-2148-11-194

学科分类：生物科学（综合）

来源: BioMed Central

【 摘 要 】

Reproductive isolation (RI) is widely accepted as an important "check point" in the diversification process, since it defines irreversible evolutionary trajectories. Much less consensus exists about the processes that might drive RI. Here, we employ a formal quantitative analysis of genetic interactions at several stages of divergence within the ring species complex Ensatina eschscholtzii in order to assess the relative contribution of genetic and ecological divergence for the development of RI. By augmenting previous genetic datasets and adding new ecological data, we quantify levels of genetic and ecological divergence between populations and test how they correlate with a restriction of genetic admixture upon secondary contact. Our results indicate that the isolated effect of ecological divergence between parental populations does not result in reproductively isolated taxa, even when genetic transitions between parental taxa are narrow. Instead, processes associated with overall genetic divergence are the best predictors of reproductive isolation, and when parental taxa diverge in nuclear markers we observe a complete cessation of hybridization, even to sympatric occurrence of distinct evolutionary lineages. Although every parental population has diverged in mitochondrial DNA, its degree of divergence does not predict the extent of RI. These results show that in Ensatina, the evolutionary outcomes of ecological divergence differ from those of genetic divergence. While evident properties of taxa may emerge via ecological divergence, such as adaptation to local environment, RI is likely to be a byproduct of processes that contribute to overall genetic divergence, such as time in geographic isolation, rather than being a direct outcome of local adaptation.

【 授权许可】

CC BY