Signature of climatic differentiation on mitochondrial DNA of Drosophila sturtevanti

Abstract

Pleistocene climatic changes have played a major role on the evolution Brazilian Atlantic Forest and South America biodiversity but their impacts on the genetic structure of widely distributed species remain unclear. Here, we investigate mitochondrial DNA (mtDNA) diversity in 21 geographical populations of Drosophila sturtevanti, Nucleotide sequences of the cytochrome C oxidase subunits I and II genes (COI and COII, respectively) from 163 individuals, showed a significant northsouth structure, in spite of an overall low level of variation. The haplotypes clustered in three groups that showed strong correlations with geographical and climatic variables, suggesting that local adaptations might have contributed to differentiation within the species. Coalescent-based analyses indicated that the three clusters have differentiated nearly ~17.000 years ago, suggesting a major role for Pleistocene changes in shaping current day distributions and differentiation of widespread Neotropical species.

Conservation Mitonuclear Replacement: Facilitated mitochondrial adaptation for a changing world

“…Mitochondrial genes appear to play an outsized role in climatic adaptation relative to their small proportion of the eukaryotic genome (Lasne et al., 2019 ). Within species, mt haplotypes commonly map onto climatic differences within a species' range (Camus et al., 2017 ; Mishmar et al., 2003 ; Rank et al., 2020 ; Silva et al., 2014 ; Wang, Ju, et al., 2021 ; Wang, Ore, et al., 2021 ; Zorzato et al., 2022 ), and experiments have demonstrated the importance of mt variation for metabolic phenotypes and thermal adaptation in both ectotherms and endotherms (Harada et al., 2019 ; Lajbner et al., 2018 ; Pichaud et al., 2012 ; Toews et al., 2014 ). Aspects of mt function with evidence of climate‐imposed selection include the functional efficiency of the individual mt electron transport system (ETS) complexes (Dingley et al., 2014 ; Harada et al., 2019 ; Pichaud et al., 2012 ) including in particular Complex I (Moran et al., 2022 ) and Complex IV (Chung et al., 2017 ; Scott et al., 2011 ), the efficiency of mt replication and transcription and the quantity of mt gene products (Bar‐Yaacov et al., 2015 ; Camus et al., 2017 ; Scott et al., 2018 ), the degree of uncoupling in the ETS (Stier, Bize, et al., 2014 ; Stier, Massemin, & Criscuolo, 2014 ), the degree of reactive oxygen species (ROS) production and/or sensitivity to ROS levels (Dingley et al., 2014 ), the propagation of the cellular stress response (Sokolova, 2018 ), the shape, fluidity, and permeability of mt membranes (Dingley et al., 2014 ), the number and volume of mitochondria (Cheng et al., 2013 ; Johnston et al., 1998 ; Scott et al., 2018 ), their rate of turnover (Sokolova, 2018 ), and their intra‐cellular position (Scott et al., 2018 ).…”