| Popis: |
Sex-lethal(Sxl)is the sex determination switch inDrosophila, and also plays a critical role in germ-line stem cell (GSC) daughter differentiation inDrosophila melanogaster. Three female-sterile alleles atSxlinDrosophila melanogasterwere previously shown to genetically interact to varying degrees with the maternally inherited endosymbiontWolbachia pipientis.Given this genetic interaction andW. pipientis’ability to manipulate reproduction inDrosophila, we carried out a careful study of both the population genetics (within fourDrosophilaspecies) and molecular evolutionary analysis (across 20Drosophilaspecies) ofSxl. Consistent with earlier studies, we find that selective constraint has played a prominent role inSxl’smolecular evolution withinDrosophila, but we also observe patterns that suggest both episodic bursts of protein evolution and recent positive selection atSxl. The episodic nature ofSxl’sprotein evolution is discussed in light of its genetic interaction withW. pipientis. |
