Abstract
Understanding the genetic mechanisms underlying particular adaptations/phenotypes of organisms is one of the core issues of evolutionary biology. The use of genomic data has greatly advanced our understandings on this issue, as well as other aspects of evolutionary biology, including molecular adaptation, speciation, and even conservation of endangered species. Despite the well-recognized advantages, usages of genomic data are still limited to non-mammal vertebrate groups, partly due to the difficulties in assembling large or highly heterozygous genomes. Although this is particularly the case for amphibians, nonetheless, several comparative and population genomic analyses have shed lights into the speciation and adaptation processes of amphibians in a complex landscape, giving a promising hope for a wider application of genomics in the previously believed challenging groups of organisms. At the same time, these pioneer studies also allow us to realize numerous challenges in studying the molecular adaptations and/or phenotypic evolutionary mechanisms of amphibians. In this review, we first summarize the recent progresses in the study of adaptive evolution of amphibians based on genomic data, and then we give perspectives regarding how to effectively identify key pathways underlying the evolution of complex traits in the genomic era, as well as directions for future research.
Highlights
Evolution can be seen as the accumulations of species’ adaptations to external environments (Dobzhansky & Gould, 1982), understanding the mechanisms underlying the organisms’ adaptations, especially at the molecular level, has been one of the core issues of evolutionary biology
We first give a brief overview of recent progresses of studies on the adaptive evolution of amphibians, and we focus our discussions by giving perspectives on the future directions for studies on adaptive evolution of amphibians, including the potential contributions of the repetitive elements on the genome evolution of amphibians
This study took advantage of the published reference genome of the N. parkeri (Sun et al, 2015) and sequenced 63 new individuals to infer the historical demography, speciation, hybridization, and potential genomic bases of adaptation to high elevations of the higher-elevation populations (Wang et al, 2018). Their results showed that natural selection plays important roles in driving and maintaining the continuing divergence within N. parkeri, and the results identified several candidate genes (e.g., CAT (Catalase), an antioxidant protein coding gene) that show high-divergence in both genetic sequences and expression levels of genes between the high- and low-elevation populations (Wang et al, 2018), which further evidence the evolution of molecular adaptations in amphibians
Summary
Evolution can be seen as the accumulations of species’ adaptations to external environments (Dobzhansky & Gould, 1982), understanding the mechanisms underlying the organisms’ adaptations, especially at the molecular level, has been one of the core issues of evolutionary biology. Their results showed that natural selection plays important roles in driving and maintaining the continuing divergence within N. parkeri, and the results identified several candidate genes (e.g., CAT (Catalase), an antioxidant protein coding gene) that show high-divergence in both genetic sequences and expression levels of genes between the high- and low-elevation populations (Wang et al, 2018), which further evidence the evolution of molecular adaptations in amphibians.
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