Molecular genetic evidence for polyandry in Ascaris suum.

The aim of this study was to determine whether single Ascaris suum female could mate with multiple males. Seven sex-linked microsatellite markers were employed and paternal genetic analyses were conducted. Totally, 62 offspring individuals from three single females were screened, and the numbers of fathers in each family were determined using allele counting methods and the program GERUD, version 2.0. The seven sex-linked microsatellite loci showed high polymorphism and revealed that one out of three families (allele counts) and two out of three families (GERUD) of the sampled families had at least two sires (2-6), indicating that females of A. suum can mate with multiple males. These findings provide the first molecular genetic evidence for polyandry of female A. suum and lay a foundation for further studies on the impacts of polyandry on population genetic parameters, the parasite population's genetic diversity, the potential for infection of different host species, and for the rate of spread of drug resistance.