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Contrasting population genetic structure among freshwater‐resident and anadromous lampreys: the role of demographic history, differential dispersal and anthropogenic barriers to movement
Author(s) -
Bracken Fiona S. A.,
Hoelzel A. Rus,
Hume John B.,
Lucas Martyn C.
Publication year - 2015
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.13112
Subject(s) - biology , fish migration , allopatric speciation , biological dispersal , lampetra , ecology , population , lamprey , sympatric speciation , genetic structure , freshwater fish , zoology , evolutionary biology , habitat , genetic variation , fishery , genetics , gene , fish <actinopterygii> , demography , sociology
The tendency of many species to abandon migration remains a poorly understood aspect of evolutionary biology that may play an important role in promoting species radiation by both allopatric and sympatric mechanisms. Anadromy inherently offers an opportunity for the colonization of freshwater environments, and the shift from an anadromous to a wholly freshwater life history has occurred in many families of fishes. Freshwater‐resident forms have arisen repeatedly among lampreys (within the P etromyzontidae and M ordaciidae), and there has been much debate as to whether anadromous lampreys, and their derived freshwater‐resident analogues, constitute distinct species or are divergent ecotypes of polymorphic species. Samples of 543 E uropean river lamprey L ampetra fluviatilis (mostly from anadromous populations) and freshwater E uropean brook lamprey L ampetra planeri from across 18 sites, primarily in the B ritish Isles, were investigated for 13 polymorphic microsatellite DNA loci, and 108 samples from six of these sites were sequenced for 829 bp of mitochondrial DNA (mt DNA ). We found contrasting patterns of population structure for mt DNA and microsatellite DNA markers, such that low diversity and little structure were seen for all populations for mt DNA (consistent with a recent founder expansion event), while fine‐scale structuring was evident for nuclear markers. Strong differentiation for microsatellite DNA loci was seen among freshwater‐resident L . planeri populations and between L . fluviatilis and L . planeri in most cases, but little structure was evident among anadromous L . fluviatilis populations. We conclude that postglacial colonization founded multiple freshwater‐resident populations with strong habitat fidelity and limited dispersal tendencies that became highly differentiated, a pattern that was likely intensified by anthropogenic barriers.