Adaptive Evolution Leads to Cross-Species Incompatibility in the piRNA Transposon Silencing Machinery
Program in Molecular Medicine; Program in Bioinformatics and Integrative Biology; Department of Biochemistry and Molecular Pharmacology
Biochemistry, Biophysics, and Structural Biology | Bioinformatics | Computational Biology | Developmental Biology | Ecology and Evolutionary Biology | Integrative Biology | Systems Biology
Reproductive isolation defines species divergence and is linked to adaptive evolution of hybrid incompatibility genes. Hybrids between Drosophila melanogaster and Drosophila simulans are sterile, and phenocopy mutations in the PIWI interacting RNA (piRNA) pathway, which silences transposons and shows pervasive adaptive evolution, and Drosophila rhino and deadlock encode rapidly evolving components of a complex that binds to piRNA clusters. We show that Rhino and Deadlock interact and co-localize in simulans and melanogaster, but simulans Rhino does not bind melanogaster Deadlock, due to substitutions in the rapidly evolving Shadow domain. Significantly, a chimera expressing the simulans Shadow domain in a melanogaster Rhino backbone fails to support piRNA production, disrupts binding to piRNA clusters, and leads to ectopic localization to bulk heterochromatin. Fusing melanogaster Deadlock to simulans Rhino, by contrast, restores localization to clusters. Deadlock binding thus directs Rhino to piRNA clusters, and Rhino-Deadlock co-evolution has produced cross-species incompatibilities, which may contribute to reproductive isolation.
adaptive evolution, chromatin, piRNA, reproductive isolation, transposon silencing
DOI of Published Version
Dev Cell. 2017 Oct 9;43(1):60-70.e5. doi: 10.1016/j.devcel.2017.08.012. Epub 2017 Sep 14. Link to article on publisher's site
Parhad, Swapnil S.; Tu, Shikui; Weng, Zhiping; and Theurkauf, William E., "Adaptive Evolution Leads to Cross-Species Incompatibility in the piRNA Transposon Silencing Machinery" (2017). Program in Bioinformatics and Integrative Biology Publications and Presentations. 121.