The individual-level approach: an original genetic field sampling scheme to optimize barrier detection in patchy populations

摘要: Landscape genetics focus on assessing the resistance of a landscape matrix by relating observed spatial genetic structure to characteristics. When studying patchy populations, studies are usually based population-level analyses, i.e. estimations distances between pairwise populations. Because low number populations only provides poor scan heterogeneity, we tested capacity an individual-based sampling at evaluating impacts structures. Using both simulated and empirical datasets, assess efficiency individual-level approach in detecting Isolation-by-Distance Isolation-by-Barrier patterns Simulated datasets were created using CDPOP, spatially explicit cost distance population program: proved be powerful methodological alternative more conventional approach, especially barrier detection. The dataset concerned widespread amphibian north-eastern France, alpine newt Ichthyosaura alpestris, outskirts two transportation infrastructures (a highway exploited since 1969, high-speed railway, 1981). study was designed so as optimize detection (30 40 year-old infrastructures, 417 genotypes sampled across 225 sites use 12 polymorphic microsatellite loci). However, no effect could detected, whatever statistical analyses carried out; contrary, highlighted unexpected pattern along highway. Although it may not possible reject hypothesis historical pattern, these results question gene flow this species: I. Alpestris actually benefit from artificial aquatic networks (transverse lengthwise water routing) for dispersal.