Autosomal suppression and fitness costs of an old driving X chromosome in Drosophila testacea.

摘要: Driving X chromosomes (XD s) bias their own transmission through males by killing Y-bearing gametes. These can in theory spread rapidly populations and cause extinction, but many are found as balanced polymorphisms or "cryptic" XD s shut down drive suppressors. The relative likelihood of these outcomes the evolutionary pathways which they come about not well understood. An was recently discovered mycophagous fly, Drosophila testacea, presenting opportunity to compare this with well-studied its sister species, neotestacea. Comparing features independently evolved young species is a promising avenue towards understanding how counteracting forces change over time. In contrast D. neotestacea, we find that D. testacea old, origin predating radiation three species: D. testacea, D. neotestacea shared orientacea. Motivated suggestion older should be more deleterious carriers, assessed effect on both male female fertility. Unlike what known from strong fitness cost females homozygous for D. testacea: large proportion failed produce offspring after being housed several days. Our fertility experiments show although lower under sperm-depleting conditions, have comparable carrying standard chromosome free-mating regime, may better approximate conditions wild testacea. Lastly, demonstrate presence autosomal suppression drive. results provide support model evolution where dynamics governed consequences males, whereas systems, likely supersede costs.