Divergence in the face of gene flow: the case of two newts (Amphibia: Salamandridae)
2009 (English)In: Molecular biology and evolution, ISSN 0737-4038, E-ISSN 1537-1719, Vol. 26, no 4, 829-841 p.Article in journal (Refereed) Published
Understanding the process of divergence requires the quantitative characterization of patterns of gene flow between diverging taxa. New and powerful coalescent-based methods give insight into these processes in unprecedented details by enabling the reconstruction of the temporal distribution of past gene flow. Here, we use sequence variation at eight nuclear markers and mitochondrial DNA (mtDNA) in multiple populations to study diversity, divergence, and gene flow between two subspecies of a salamander, the smooth newt (Lissotriton vulgaris kosswigi and Lissotriton vulgaris vulgaris) in Turkey. The ranges of both subspecies encompass mainly the areas of this important glacial refugial area. Populations in refugia where species have been present for a long time and differentiated in situ should better preserve the record of past gene flow than young populations in postglacial expansion areas. Sequence diversity in both subspecies was substantial (nuclear πsil = 0.69% and 1.31%). We detected long-term demographic stability in these refugial populations with large effective population sizes (Ne) of the order of 1.5–3 × 105 individuals. Gene trees and the isolation with migration (IM) analysis complemented by tests of nested IM models showed that despite deep, pre-Pleistocene divergence of the studied newts, asymmetric introgression from vulgaristo kosswigi has occurred, with signatures of recent gene flow in mtDNA and an anonymous nuclear marker, and evidence for more ancient introgression in nuclear introns. The distribution of migration times raises the intriguing possibility that even the initial divergence may have occurred in the face of gene flow.
Place, publisher, year, edition, pages
2009. Vol. 26, no 4, 829-841 p.
IdentifiersURN: urn:nbn:se:uu:diva-238106DOI: 10.1093/molbev/msp004OAI: oai:DiVA.org:uu-238106DiVA: diva2:770049