Genetic analysis and management in small populations: the Asturcon pony as an example

Geneticists are faced with various problems when managing small natural populations (e.g. high inbreeding, loss of economic value). We propose here the management of a small population through the example of the Asturcon (a Celtic pony population) by examining two sources of information: a studbook created in 1981 and the polymorphism of ten microsatellite markers chosen according to the recommendations of ISAG (International Society of Animal Genetics). This information allows us to estimate several genetic parameters useful in assessing the genetic situation of the population in order to propose conservation strategies. Results show the reliability of molecular information in populations where no studbook exists. Overall inbreeding value (F) and fixation index (F-IT) are moderate (F = 0.027; F-IT = 0.056), effective number of founders is small (n = 22), and the population is divided into three distinct groups (F-ST = 0.078; P < 0.001). The molecular heterozygosity (H-M = 71.2%) computed in a random sample gives an accurate vision of the real inbreeding. These parameters and the application of the concept of average relatedness allow us to recommend to the breeders the choice of the best matings to control the inbreeding level while maintaining a low paternity error rate. (C) Inra/Elsevier, Paris.