title: Mitochondrial Involvement in Vertebrate Speciation? The Case of Mito-nuclear Genetic Divergence in Chameleons.
abstract: Compatibility between the nuclear (nDNA) and mitochondrial (mtDNA) genomes is important for organismal health. However, its significance for major evolutionary processes such as speciation is unclear, especially in vertebrates. We previously identified a sharp mtDNA-specific sequence divergence between morphologically indistinguishable chameleon populations (Chamaeleo chamaeleon recticrista) across an ancient Israeli marine barrier (Jezreel Valley). Because mtDNA introgression and gender-based dispersal were ruled out, we hypothesized that mtDNA spatial division was maintained by mito-nuclear functional compensation. Here, we studied RNA-seq generated from each of ten chameleons representing the north and south populations and identified candidate nonsynonymous substitutions (NSSs) matching the mtDNA spatial distribution. The most prominent NSS occurred in 14 nDNA-encoded mitochondrial proteins. Increased chameleon sample size (N = 70) confirmed the geographic differentiation in POLRMT, NDUFA5, ACO1, LYRM4, MARS2, and ACAD9. Structural and functionality evaluation of these NSSs revealed high functionality. Mathematical modeling suggested that this mito-nuclear spatial divergence is consistent with hybrid breakdown. We conclude that our presented evidence and mathematical model underline mito-nuclear interactions as a likely role player in incipient speciation in vertebrates.
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Bar-Yaacov
authors.affiliation: Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, UCL, London, United Kingdom Department of Genetics, Evolution and Environment, UCL, London, United Kingdom.
authors.forename: Zena
authors.initials: Z
authors.lastname: Hadjivasiliou
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
authors.forename: Liron
authors.initials: L
authors.lastname: Levin
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
authors.forename: Gilad
authors.initials: G
authors.lastname: Barshad
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
authors.forename: Raz
authors.initials: R
authors.lastname: Zarivach
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel.
authors.forename: Amos
authors.initials: A
authors.lastname: Bouskila
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel dmishmar@bgu.ac.il.
authors.forename: Dan
authors.initials: D
authors.lastname: Mishmar
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D050259:Genes, Mitochondrial; D049810:Genetic Speciation; D007076:Iguanas / Q000235:genetics*; D008957:Models, Genetic; D011110:Polymorphism, Genetic
keywords: RNA-seq; mito-nuclear coevolution; mitochondrial DNA; nuclear DNA; speciation; transcriptome