GENETIC ANALYSIS OF COMPLEX DEMOGRAPHIC SCENARIOS: SPATIALLY EXPANDING POPULATIONS OF THE CANE TOAD,BUFO MARINUS

摘要: Inferring the spatial expansion dynamics of invading species from molecular data is notoriously difficult due to complexity processes involved. For these demographic scenarios, genetic obtained highly variable markers may be profitably combined with specific sampling schemes and information other sources using a Bayesian approach. The geographic range introduced toad Bufo marinus still expanding in eastern northern Australia, each case isolates established around 1960. A large amount historical available on both areas. In area, samples were collected along transect representing populations different ages genotyped at 10 microsatellite loci. Five models expansion, differing dispersal pattern for migrants founders number founders, considered. Because history complex, we used an approximate method, based rejection-regression algorithm, formally test relative likelihoods five infer parameters. stepwise migration-foundation model founder events was statistically better supported than four Posterior distributions studied Populations area have lower stable effective population size been founded by smaller individuals those area. Once demographically stabilized, exchange substantial per generation areas, such exchanges are larger Australia. appears considerably that We found our inferences relatively robust various assumptions marker, demographic, features. method presented here only robust, model-based so far, which allows inferring complex over short time scale. It also provides basis investigating interplay between dynamics, drift, selection invasive species.