Evidence for feminized genetic males in a flea beetle using newly identified X-linked markers.

The equilibrium of sex ratios in sexually reproducing species is often disrupted by various environmental and genetic factors, including endosymbionts like . In this study, we explore the highly female-biased sex ratio observed in the flea beetle, , and its underlying mechanisms. Ancient hybridization events between species have led to mitochondrial DNA introgression, resulting in distinct mitochondrial haplotypes that go along with different infections (HT1-wLytA1, HT1*- uninfected, HT2-wLytA2, and HT3-wLytB).

Recent Evolution of a Maternally Acting Sex-Determining Supergene in a Fly with Single-Sex Broods.

Sex determination is a key developmental process, yet it is remarkably variable across the tree of life. The dipteran family Sciaridae exhibits one of the most unusual sex determination systems in which mothers control offspring sex through selective elimination of paternal X chromosomes. Whereas in some members of the family females produce mixed-sex broods, others such as the dark-winged fungus gnat Bradysia coprophila are monogenic, with females producing single-sex broods.