Simultaneous delimitation of species and quantification of interspecific hybridization in Amazonian peacock cichlids (genus cichla ) using multi-locus data

BMC Evolutionary Biology

Guillermo Ort¹  Jason Macrander²  Izeni P Farias³  Stuart C Willis⁴ 

[1] Department of Biology, The George Washington University, Washington, USA;Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, USA;Laboratrio de Evoluo e Gentica Animal, ICB, Universidade Federal do Amazonas, Manaus, Brazil;School of Biological Sciences, 348 Manter Hall, University of Nebraska-Lincoln, Lincoln, USA

关键词: Gene Flow;    Species Concept;    Putative Hybrid;    Introgressive Hybridization;    Putative Species;   

DOI  :  10.1186/1471-2148-12-96

学科分类：生物科学（综合）

来源: BioMed Central

【 摘 要 】

Introgression likely plays a significant role in evolution, but understanding the extent and consequences of this process requires a clear identification of species boundaries in each focal group. The delimitation of species, however, is a contentious endeavor. This is true not only because of the inadequacy of current tools to identify species lineages, but also because of the inherent ambiguity between natural populations and species paradigms. The result has been a debate about the supremacy of various species concepts and criteria. Here, we utilized multiple separate sources of molecular data, mtDNA, nuclear sequences, and microsatellites, to delimit species under a polytypic species concept (PTSC) and estimate the frequency and genomic extent of introgression in a Neotropical genus of cichlid fishes (Cichla). We compared our inferences of species boundaries and introgression under this paradigm to those when species are identified under a diagnostic species concept (DSC). We find that, based on extensive molecular data and an inclusive species concept, 8 separate biological entities should be recognized rather than the 15 described species of Cichla. Under the PTSC, fewer individuals are expected to exhibit hybrid ancestry than under the DSC (~2% vs. ~12%), but a similar number of the species exhibit introgression from at least one other species (75% vs. 60%). Under either species concept, the phylogenetic breadth of introgression in this group is notable, with both sister species and species from different major mtDNA clades exhibiting introgression. Introgression was observed to be a widespread phenomenon for delimited species in this group. While several instances of introgressive hybridization were observed in anthropogenically altered habitats, most were found in undisturbed natural habitats, suggesting that introgression is a natural but ephemeral part of the evolution of many tropical species. Nevertheless, even transient introgression may facilitate an increase in genetic diversity or transfer of adaptive mutations that have important consequences in the evolution of tropical biodiversity.

【 授权许可】

CC BY