02895nas a2200301 4500008004100000245008000041210006900121260003000190300001100220490000600231520198100237100001902218700002002237700001902257700002002276700002202296700001902318700002402337700002102361700002302382700002202405700002602427700002702453700002102480700002802501700002002529856004402549 2014 eng d00aHigh Rates of Gene Flow by Pollen and Seed in Oak Populations across Europe0 aHigh Rates of Gene Flow by Pollen and Seed in Oak Populations ac bPublic Library of Science ae851300 v93 a

Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe.

Adult trees within a given area in each stand were exhaustively sampled (range [239, 754], mean 423), mapped, and acorns were collected ([17,147], 51) from several mother trees ([3], [47], 23). Seedlings ([65,387], 178) were harvested and geo-referenced in six of the eight stands. Genetic information was obtained from screening distinct molecular markers spread across the genome, genotyping each tree, acorn or seedling. All samples were thus genotyped at 5–8 nuclear microsatellite loci. Fathers/parents were assigned to acorns and seedlings using likelihood methods. Mating success of male and female parents, pollen and seed dispersal curves, and also hybridisation rates were estimated in each stand and compared on a continental scale.

On average, the percentage of the wind-borne pollen from outside the stand was 60%, with large variation among stands (21–88%). Mean seed immigration into the stand was 40%, a high value for oaks that are generally considered to have limited seed dispersal. However, this estimate varied greatly among stands (20–66%). Gene flow was mostly intraspecific, with large variation, as some trees and stands showed particularly high rates of hybridisation.

Our results show that mating success was unevenly distributed among trees. The high levels of gene flow suggest that geographically remote oak stands are unlikely to be genetically isolated, questioning the static definition of gene reserves and seed stands.

1 aGerber, Sophie1 aChadœuf, Joël1 aGugerli, Felix1 aLascoux, Martin1 aBuiteveld, Joukje1 aCottrell, Joan1 aDounavi, Aikaterini1 aFineschi, Silvia1 aForrest, Laura, L.1 aFogelqvist, Johan1 aGoicoechea, Pablo, G.1 aJensen, Jan, Svejgaard1 aSalvini, Daniela1 aVendramin, Giovanni, G.1 aKremer, Antoine uhttps://quercus.myspecies.info/node/16002840nas a2200229 4500008004100000020001400041245016200055210006900217300001200286520205300298653002502351653001302376653002002389653002002409100002302429700002102452700002102473700002002494700002802514700002402542856004402566 2012 eng d a1095-831200aA landscape genetics approach reveals ecological-based differentiation in populations of holm oak (Quercus ilex L.) at the northern limit of its range0 alandscape genetics approach reveals ecologicalbased differentiat an/a-n/a3 aThe holm oak plays a relevant role in the functioning of Mediterranean forests. In the area north of Garda Lake, Italian Prealps, holm oak populations are at the northernmost edge of their distribution. Being peripheral, these populations are of particular interest for ecological, evolutionary and conservation studies. Through an explicit individual-based landscape genetics approach, we addressed the following questions: (1) are levels of genetic variation reduced in these marginal populations compared with central populations?; (2) despite the narrow geographical scale, do individual-based analyses have some power to detect genetic differentiation?; (3) do environmental and/or climatic factors exert a role in shaping patterns of genetic variation and differentiation? Through a Bayesian method, we identified three clusters whose genetic variability can be considered to be of the same order as that recorded in central Quercus ilex populations. Although being geographically very close (< 20 km), the differentiation was statistically significant (P < 0.05) with global F st and ΦPt values of 0.019 and 0.038, respectively. Geography and phylogeography could not be invoked to explain this differentiation. A redundancy discriminant analysis revealed that relevant eco-pedological and climatic features, such as soil depth, aspect, elevation and humidity, were correlated with the observed pattern of differentiation. Toblino was ecologically separated from the other clusters, as it lies on deep soil with subhumid conditions. The differentiation of the Brione–Ranzo–Val Busa cluster appeared to be related to superficial soils and drier conditions, whereas the Nanzone–Padaro cluster was differentiated mainly according to its mid-elevation. Coupling spatial and genetic information on a local scale proved to be effective to investigate the evolutionary and demographic history of peripheral populations. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.10aBayesian computation10aGeneland10aItalian Prealps10amicrosatellites1 aVernesi, Cristiano1 aRocchini, Duccio1 aPecchioli, Elena1 aNeteler, Markus1 aVendramin, Giovanni, G.1 aPaffetti, Donatella uhttps://quercus.myspecies.info/node/151