Journal
MOLECULAR BIOLOGY AND EVOLUTION
Volume 34, Issue 10, Pages 2522-2536Publisher
OXFORD UNIV PRESS
DOI: 10.1093/molbev/msx167
Keywords
molecular evolution; respiratory physiology; ecomorphology; mitochondria; Cryptodira
Funding
- Fundacao para a Ciencia e a Tecnologia (FCT) [SFRH/BPD/66448/2009]
- FCT [UID/Multi/04423/2013]
- European Regional Development Fund (ERDF)
- European Structural and Investment Funds (ESIF) under the Competitiveness and Internationalization Operational Program-COMPETE through FCT [PTDC/AAG-GLO/6887/2014 (POCI-01-0124-FEDER-016845)]
- Structure Programs RDI INNOVMAR [NORTE-01-0145-FEDER-000035-NOVELMAR]
- CORAL NORTE [NORTE-01-0145-FEDER-000036]
- Northern Regional Operational Program (NORTE) through ERDF
- Fundação para a Ciência e a Tecnologia [SFRH/BPD/66448/2009] Funding Source: FCT
Ask authors/readers for more resources
The mitochondrial genome encodes several protein components of the oxidative phosphorylation (OXPHOS) pathway and is critical for aerobic respiration. These proteins have evolved adaptively in many taxa, but linking molecular-level patterns with higher-level attributes (e.g., morphology, physiology) remains a challenge. Turtles are a promising system for exploring mitochondrial genome evolution as different species face distinct respiratory challenges and employ multiple strategies for ensuring efficient respiration. One prominent adaptation to a highly aquatic lifestyle in turtles is the secondary loss of keratenized shell scutes (i.e., soft-shells), which is associated with enhanced swimming ability and, in some species, cutaneous respiration. We used codon models to examine patterns of selection on mitochondrial protein-coding genes along the three turtle lineages that independently evolved soft-shells. We found strong evidence for positive selection along the branches leading to the pig-nosed turtle (Carettochelys insculpta) and the softshells clade (Trionychidae), but only weak evidence for the leatherback (Dermochelys coriacea) branch. Positively selected sites were found to be particularly prevalent in OXPHOS Complex I proteins, especially subunit ND2, along both positively selected lineages, consistent with convergent adaptive evolution. Structural analysis showed that many of the identified sites are within key regions or near residues involved in proton transport, indicating that positive selection may have precipitated substantial changes in mitochondrial function. Overall, our study provides evidence that physiological challenges associated with adaptation to a highly aquatic lifestyle have shaped the evolution of the turtle mitochondrial genome in a lineage-specific manner.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available