title: Surfing in tortoises? Empirical signs of genetic structuring owing to range expansion.
abstract: Much of our current knowledge about the genetic dynamics in range expansions originates from models, simulations and microcosm experiments that need to be corroborated by field data. Here, we report a neutral genetic pattern that matches the predictions of the genetic surfing theory. Genetic surfing occurs when repeated founding events and genetic drift act on the wave of advance of an expanding population, promoting strong spatial structure. In the range expansion of the tortoise Testudo graeca from North Africa to southeastern Spain, we found several genetic signatures consistent with surfing: a decrease of genetic diversity with distance from the initial founder area, clinal patterns in allele frequencies, rare African alleles which have become common at distal sites in the Spanish range, and stronger spatial differentiation in the expanded range than in the original one. Our results provide support for the theory that genetic drift can be an important force in shaping the genetic structure of expanding populations.
authors.affiliation: Area of Ecology, Department of Applied Biology, Miguel Hernández University, , Avenida de la Universidad, Torreblanca, 03202 Elche, Spain. egracia@umh.es
authors.forename: Eva
authors.initials: E
authors.lastname: Graciá
authors.forename: Francisco
authors.initials: F
authors.lastname: Botella
authors.forename: José Daniel
authors.initials: JD
authors.lastname: Anadón
authors.forename: Pim
authors.initials: P
authors.lastname: Edelaar
authors.forename: D James
authors.initials: DJ
authors.lastname: Harris
authors.forename: Andrés
authors.initials: A
authors.lastname: Giménez
mesh_terms: D025041:Animal Migration; D000818:Animals; D036262:Empirical Research; D040961:Genetic Drift; D014644:Genetic Variation; D014426:Turtles / Q000235:genetics / Q000502:physiology*
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