WGS of Osmia bicornis, haploid and diploid males and diploid females, with the aim of identifying their complementary sex determination locus

Species from the order Hymenoptera, including the red mason bee Osmia bicornis, have a haplo-diploid sex determination system where females are diploid and males are usually haploid. In many species this is controlled by a complementary sex determination locus (CSD), which is heterozygous in females and homo- or hemizygous in males. In this project, we have sequenced diploid males in order to identify homozygous candidate regions for the CSD locus in O. bicornis. Many diploid males have high homozygosity overall due to inbreeding, but the candidate regions could be narrowed down by looking for regions that are not only homozygous in diploid males but also heterozygous in inbred females from the same nests. Other randomly selected females have also been sequenced as well as males which after sequence analysis proved to be haploid.