Journal Article
Adaptive evolution of mitochondrial genomes in Triplophysa cavefishes
Zhang, J., Shu, L. and Peng, Z.
Record Number:
6311
Year:
2024
Journal:
Gene
Pages:
1-9
Volume:
893 147947
Abstract:
Extreme conditions in caves pose survival challenges for cave dwellers, who gradually develop adaptive survival
features. Cavefishes are one of the most successful animals among cave dwellers. Triplophysa cavefishes are an
important group of cavefishes, and they show remarkable adaptability to the extreme environments of caves.
However, there is a limited understanding of their adaptation mechanisms. In this study, eight complete mitochondrial
genomes of Triplophysa cavefishes were newly obtained, and their genomic characteristics, including
the base composition, base bias, and codon usage, were analyzed. Phylogenetic analysis was carried out based on
13 mitochondrial protein-coding genes from 44 Nemacheilidae species. This showed that Triplophysa cavefishes
and non-cavefishes separate into two reciprocally monophyletic clades, suggesting a single origin of the cave
phenotype. Positive selection analysis strongly suggested that the selection pressure in cavefishes is higher than
that in non-cavefishes. Furthermore, the ND5 gene in cavefishes showed evidence of positive selection, which
suggests that the gene may play an important role in the adaptation of cavefishes to the cave environment.
Protein structure analysis of the ND5 subunit implied that the sites of positive selection in cavefishes might allow
them to acquire lower ND5 protein stability, compared to that in non-cavefishes, which might help the accumulation
of nonsynonymous (mildly deleterious) mutations. Together, our study revealed the genetic signatures
of cave adaptation in Triplophysa cavefishes from the perspective of energy metabolism.
Times Cited:
2