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A question of time: the land snail M urella muralis ( G astropoda: P ulmonata) reveals constraints on past ecological speciation
Author(s) -
Fiorentino V.,
Manganelli G.,
Giusti F.,
Tiedemann R.,
Ketmaier V.
Publication year - 2013
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.12107
Subject(s) - land snail , biology , genetic algorithm , ecology , population , ecological speciation , snail , habitat , selection (genetic algorithm) , local adaptation , genetic divergence , incipient speciation , divergence (linguistics) , evolutionary biology , genetic variation , gene , gene flow , genetic diversity , genetics , demography , sociology , linguistics , philosophy , artificial intelligence , computer science
Abstract The lively debate about speciation currently focuses on the relative importance of factors driving population differentiation. While many studies are increasingly producing results on the importance of selection, little is known about the interaction between drift and selection. Moreover, there is still little knowledge on the spatial‐temporal scales at which speciation occurs, that is, arrangement of habitat patches, abruptness of habitat transitions, climate and habitat changes interacting with selective forces. To investigate these questions, we quantified variation on a fine geographical scale analysing morphological (shell) and genetic data sets coupled with environmental data in the land snail M urella muralis , endemic to the M editerranean island of S icily. Analysis of a fragment of the mitochondrial DNA cytochrome oxidase I gene ( COI ) and eight nuclear microsatellite loci showed that genetic variation is highly structured at a very fine spatial scale by local palaeogeographical events and historical population dynamics. Molecular clock estimates, calibrated here specifically for T yrrhenian land snails, provided a framework of palaeogeographical events responsible for the observed geographical variations and migration routes. Finally, we showed for the first time well‐documented lines of evidence of selection in the past, which explains divergence of land snail shell shapes. We suggest that time and palaeogeographical history acted as constraints in the progress along the ecological speciation continuum. Our study shows that testing for correlation among palaeogeography, morphology and genetic data on a fine geographical scale provides information fundamental for a detailed understanding of ecological speciation processes.