Analysis of relatedness and determination of the source of founders in the captive bearded vulture, Gypaetus barbatus, population

Genetic relatedness among founders is a vital parameter in the management of captive populations as kin structure can have a significant effect on subsequent population structure. Methods for inferring relatedness from microsatellite markers have all been developed for natural populations; their applicability to captive populations with unknown founder origins needs therefore testing. We used information derived from 14 microsatellites in 177 individuals and Queller and Goodnight's approach, to estimate relatedness in the captive bearded vulture population and to test the assumption of unrelated founders. Mean relatedness of known parent-offspring, full-sib and half-sib pairs within the captive population were in agreement with theoretical distributions. Pairwise relatedness values among the founders had a mean of -0.051 (SE +/- 0.007) and their distribution did only differ marginally from the one found in the natural Pyrenean population. A maximum likelihood approach was used to determine the likelihood of founder pairs to be as closely related as full-sibs or parent-offspring. These results were combined with data from 268 bp mitochondrial DNA control region sequences and studbook information. We could exclude a close relationship among the majority of the 36 successfully reproducing founders. Our study therefore removes management concerns about hidden problems of inbreeding and inbreeding depression. It demonstrates the applicability of relatedness estimates based on microsatellite allele frequency data even in captive populations. Furthermore, we verified studbook information on the origin of two founders from the Pyrenees, and show the value of assignment tests based on microsatellites for deducing founder origins and their important role in future monitoring projects.