Demographic modeling with whole genome data reveals parallel origin of similar Pundamilia cichlid species after hybridization

Meier, Joana; Martins Conde e Sousa, Vitor; Marques, David Alexander; Selz, Oliver; Wagner, Catherine; Excoffier, Laurent; Seehausen, Ole (2016). Demographic modeling with whole genome data reveals parallel origin of similar Pundamilia cichlid species after hybridization. Molecular Ecology, 26(1), pp. 123-141. Wiley-Blackwell 10.1111/mec.13838

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Modes and mechanisms of speciation are best studied in young species pairs. In older taxa it is increasingly difficult to distinguish what happened during speciation from what happened after speciation. Lake Victoria cichlids in the genus Pundamilia encompass a complex of young species and polymorphic populations. One Pundamilia species pair, P. pundamilia and P. nyererei, is particularly well-suited to study speciation because sympatric population pairs occur with different levels of phenotypic differentiation and reproductive isolation at different rocky islands within the lake. Genetic distances between allopatric island populations of the same nominal species often exceed those between the sympatric species. It thus remained unresolved whether speciation into P. nyererei and P. pundamilia occurred once, followed by geographical range expansion and interspecific gene flow in local sympatry, or if the species pair arose repeatedly by parallel speciation. Here we use genomic data and demographic modeling to test these alternative evolutionary scenarios. We demonstrate that gene flow plays a strong role in shaping the observed patterns of genetic similarity, including both gene flow between sympatric species and gene flow between allopatric populations, as well as recent and early gene flow. The best supported model for the origin of P. pundamilia and P. nyererei population pairs at two different islands is one where speciation happened twice, whereby the second speciation event follows shortly after introgression from an allopatric P. nyererei population that arose earlier. Our findings support the hypothesis that very similar species may arise repeatedly, potentially facilitated by introgressed genetic variation.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Population Genetics
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Aquatic Ecology

UniBE Contributor:

Meier, Joana; Martins Conde e Sousa, Vitor; Marques, David Alexander; Selz, Oliver; Wagner, Catherine; Excoffier, Laurent and Seehausen, Ole

Subjects:

500 Science > 570 Life sciences; biology

ISSN:

0962-1083

Publisher:

Wiley-Blackwell

Language:

English

Submitter:

Marcel Häsler

Date Deposited:

26 Sep 2016 14:58

Last Modified:

10 Sep 2017 08:30

Publisher DOI:

10.1111/mec.13838

PubMed ID:

27613570

BORIS DOI:

10.7892/boris.88256

URI:

https://boris.unibe.ch/id/eprint/88256

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