Data from: Asexual male production by ZW recombination in Artemia parthenogenetica

In some asexual species, parthenogenetic females occasionally produce
males, which may strongly affect the evolution and maintenance of
asexuality if they cross with related sexuals and transmit genes causing
asexuality to their offspring (“contagious parthenogenesis”). How these
males arise in the first place has remained enigmatic, especially in
species with sex chromosomes. Here, we test the hypothesis that rare,
asexually produced males of the crustacean Artemia
parthenogenetica are produced by recombination between the Z and W sex
chromosomes during non-clonal parthenogenesis, resulting in ZZ males
through loss of heterozygosity at the sex determination locus. We used
RAD-sequencing to compare asexual mothers with their male and female
offspring. Markers on several sex-chromosome scaffolds indeed lost
heterozygosity in all male but no female offspring, suggesting that they
correspond to the sex-determining region. Other sex-chromosome scaffolds
lost heterozygosity in only a part of the male offspring, consistent with
recombination occurring at a variable location. Alternative hypotheses for
the production of these males (such as partial or total hemizygosity of
the Z) could be excluded. Rare males are thus produced because
recombination is not entirely suppressed during parthenogenesis in A.
parthenogenetica. This finding may contribute to explaining the
maintenance of recombination in these asexuals.