The Elusive Nature of Adaptive Mitochondrial DNA Evolution of an Arctic Lineage Prone to Frequent Introgression

• Published in: Genome Biology and Evolution
• Main Authors: Melo-Ferreira, José, Vilela, Joana, Fonseca, Miguel, da Fonseca, Rute, R, Boursot, Pierre, Alves, Paulo, C.
• Other Authors: Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO-UP), Universidade do Porto = University of Porto-CESPU, Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO), Centro de Investigacão em Biodiversidade e Recursos Genéticos (CIBIO), Universidade do Porto = University of Porto, Faculdade de Ciências da Universidade do Porto (FCUP), Universidade de Vigo, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: This project has been deposited at GenBank under the accessions KJ397605; KJ397606; KJ397607; KJ397608; KJ397609; KJ397610; KJ397611; KJ397612; KJ397613; and KJ397614 mitogenomics; Lepus; codon evolution; d N /d S; protein structure; positive selection; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; Arctic
• Online Access: https://hal.umontpellier.fr/hal-02347339; https://hal.umontpellier.fr/hal-02347339/document; https://hal.umontpellier.fr/hal-02347339/file/evu059.pdf; https://doi.org/10.1093/gbe/evu059

International audience Mitochondria play a fundamental role in cellular metabolism, being responsible for most of the energy production of the cell in the oxidative phosphorylation (OXPHOS) pathway. Mitochondrial DNA (mtDNA) encodes for key components of this process, but its direct role in adaptation remains far from understood. Hares (Lepus spp.) are privileged models to study the impact of natural selection on mitogenomic evolution because 1) species are adapted to contrasting environments, including arctic, with different metabolic pressures, and 2) mtDNA introgression from arctic into temperate species is widespread. Here, we analyzed the sequences of 11 complete mitogenomes (ten newly obtained) of hares of temperate and arctic origins (including two of arctic origin introgressed into temperate species). The analysis of patterns of codon substitutions along the reconstructed phylogeny showed evidence for positive selection in several codons in genes of the OXPHOS complexes, most notably affecting the arctic lineage. However, using theoretical models, no predictable effect of these differences was found on the structure and physicochemical properties of the encoded proteins, suggesting that the focus of selection may lie on complex interactions with nuclear encoded peptides. Also, a cloverleaf structure was detected in the control region only from the arctic mtDNA lineage, which may influence mtDNA replication and transcription. These results suggest that adaptation impacted the evolution of hare mtDNA and may have influenced the occurrence and consequences of the many reported cases of massive mtDNA introgression. However, the origin of adaptation remains elusive.