Genomic population structure of sympatric sexual and asexual populations in a parasitic wasp, Meteorus pulchricornis (Hymenoptera: Braconidae), inferred from six hundred single-nucleotide polymorphism loci.

In spite of the two-fold reproductive advantage, asexual reproduction is not common in nature, probably due to the associated genetic deterioration or reduced genetic variation. To understand how genetic diversity is maintained in existing asexual populations, we investigated the genetic diversity and population structure of sympatric sexual and asexual populations of a parasitic wasp, Meteorus pulchricornis, using 614 genome-wide single nucleotide polymorphisms. The genetic structures of the apomictic asexual populations were distinct, showing considerable genetic differentiation among them. Most of the asexual populations were highly differentiated from the sympatric sexual population; some asexual individuals could not be distinguished from members of the sexual population. Furthermore, significantly fewer multilocus genotypes were identified in the asexual populations (1-7) compared to the sexual population (42), which is consistent with their apomictic nature. The observed patterns of fixed heterozygous sites suggest that most asexual populations had the same evolutionary origin and have long since evolved individually; the detected gene flow between the sexual population and a few asexual population may indicate independent origins of asexuality. The potential role of occasional males in apomictic wasps is also discussed.