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Author(s): Escalona T.
Weadick C.J.
Antunes A.
Title: Adaptive Patterns of Mitogenome Evolution Are Associated with the Loss of Shell Scutes in Turtles
Publisher: Oxford University Press
Issue Date: 2017
Abstract: 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. © 2017 The Author 2017.
Subject: reduced nicotinamide adenine dinucleotide dehydrogenase (ubiquinone)
animal shell
Carettochelys insculpta
convergent evolution
Dermochelys coriacea
mitochondrial genome
oxidative phosphorylation
proton transport
structure analysis
Source: Molecular Biology and Evolution, vol. 34(10), p. 2522-2536
Related Information: info:eu-repo/grantAgreement/FCT/5876/147268/PT
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:CIIMAR - Artigo em Revista Científica Internacional

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