A prominent role of KRAB-ZNF transcription factors in mammalian speciation?

The mechanisms of speciation have been one of the most debated topics in evolutionary biology. Among all reproductive barriers, postzygotic reproductive isolation is perhaps the one that has attracted the most attention from geneticists. Despite remarkable advances in the identification of loci involved in Drosophila speciation, little is known about the genes, functions, and biochemical interactions of the molecules underlying hybrid sterility and inviability in mammals. Here, we discuss the main evolutionary and molecular features that make transcription factors (TFs), especially the family of zinc finger proteins with a Krüppel-associated box domain (KRAB-ZNF), strong candidates to play an important role in postzygotic reproductive isolation. Motivated by the recent identification of the gene encoding PR domain zinc finger protein 9 (Prdm9; a KRAB-ZNF gene) as the first hybrid sterility gene identified in mammals, we further propose integrative approaches to study KRAB-ZNF genes with the main goal of characterizing the molecular pathways and interactions involved in hybrid incompatibilities. © 2012 Elsevier Ltd.K.N.’s research is funded by the Volkswagen Foundation within the initiative ‘Evolutionary Biology’. M.C. and R.F. both have a postdoc fellowship financed by the Portuguese Science Foundation (FCT) through the programs COMPETE (SFRH/BPD/72343/2010 and SFRH/BPD/26384/2006, respectively). R.F.’s research is also financed by FCT through the research project PTDC/BIA-EVF/113805/2009. This manuscript originated within the framework of a research collaboration funded by the program ‘Acções Integradas Luso-Alemãs/DAAD’ awarded to K.N. and R.F.Peer Reviewe