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Evolutionary patterns in squamate mitogenomes: Are selective regimes associated with fossoriality and limblessness?
Anieli Guirro Pereira1, Vinicius Anelli1, Rubens Pasa2
1Universidade de São Paulo, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Departamento de Biologia, Laboratório de Evolução e Biologia Integrativa, Ribeirão Preto, SP, Brazil.
Genetics and Molecular Biology
|July 20, 2026
Summary
Fossoriality, or burrowing, significantly impacts mitochondrial gene evolution in squamates more than limblessness. This study on Amphisbaena alba reveals distinct selective pressures on mitochondrial genomes due to burrowing behaviors.
Area of Science:
- Evolutionary Biology
- Genomics
- Molecular Biology
Background:
- The snakelike phenotype, characterized by limb reduction and body elongation, has evolved independently in various vertebrate lineages.
- This phenotype is often linked to adaptations for fossoriality (burrowing) or complex habitats.
- Locomotion in limbless and fossorial species may impose different energetic demands, potentially influencing mitochondrial gene evolution.
Purpose of the Study:
- To investigate the impact of limblessness versus fossoriality on mitochondrial genome evolution in Squamata.
- To analyze the mitochondrial genome of Amphisbaena alba and compare selective pressures across different squamate lineages.
Main Methods:
- Sequencing and assembly of the complete mitochondrial genome of Amphisbaena alba (16,800 bp).
- Comparative analysis of mitochondrial gene evolution using selective tests.
- Differentiating selective rates for clades with limbless and fossorial species.
Main Results:
- The Amphisbaena alba mitochondrial genome comprises standard components: 13 protein-coding genes, 22 tRNAs, 2 rRNAs, and a control region.
- Fossorial species exhibited significant changes in selective rates across more mitochondrial genes compared to limbless species.
- This suggests fossoriality is a more dominant factor influencing selective pressures on mitochondrial genes in Squamata.
Conclusions:
- Fossoriality appears to be a stronger driver of mitochondrial genome evolution in Squamates than limblessness.
- Understanding these pressures provides insights into adaptation and evolutionary trajectories in reptiles.
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