Open AccessGenetic differentiation on multiple spatial scales in an ecotype‐forming marine snail with limited dispersal: Littorina saxatilis
Author(s) -
MÄKINEN TUULI,
PANOVA MARINA,
JOHANNESSON KERSTIN,
TATARENKOV ANDREY,
APPELQVIST CHRISTIN,
ANDRÉ CARL
Publication year - 2008
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2008.00960.x
Subject(s) - biology , genetic structure , biological dispersal , isolation by distance , gene flow , ecology , population , reproductive isolation , local adaptation , littorina , genetic drift , ecotype , evolutionary biology , selection (genetic algorithm) , genetic variation , gastropoda , gene , genetics , demography , sociology , artificial intelligence , computer science
The population genetic structure of marine species lacking free‐swimming larvae is expected to be strongly affected by random genetic drift among populations, resulting in genetic isolation by geographical distance. At the same time, ecological separation over microhabitats followed by direct selection on those parts of the genome that affect adaptation might also be strong. Here, we address the question of how the relative importance of stochastic vs. selective structuring forces varies at different geographical scales. We use microsatellite DNA and allozyme data from samples of the marine rocky shore snail Littorina saxatilis over distance scales ranging from metres to 1000 km, and we show that genetic drift is the most important structuring evolutionary force at distances > 1 km. On smaller geographical scales (< 1 km), divergent selection between contrasting habitats affects population genetic structure by impeding gene flow over microhabitat borders (microsatellite structure), or by directly favouring specific alleles of selected loci (allozyme structure). The results suggest that evolutionary drivers of population genetic structure cannot a priori be assumed to be equally important at different geographical scales. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 31–40.