Publication
Mitochondrial genomes reveal mid-Pleistocene population divergence, and post-glacial expansion, in Australasian snapper (Chrysophrys auratus)
Publisher:
Springer Science and Business Media LLC
Date:
03-12-2022
DOI:
10.1038/S41437-022-00579-1
Abstract: Glacial cycles play important roles in determining the phylogeographic structure of terrestrial species, however, relatively little is known about their impacts on the distribution of marine biota. This study utilised modern ( n = 350) and ancient ( n = 26) mitochondrial genomes from Australasian snapper ( Chrysophrys auratus ) s led in New Zealand to assess their demographic and phylogeographic history. We also tested for changes in genetic ersity using the up to 750-year-old mitochondrial genomes from pre-European archaeological sites to assess the potential impacts of human exploitation. Nucleotide ersity and haplotype ersity was high (π = 0.005, h = 0.972). There was no significant change in nucleotide ersity over the last 750 years ( p = 0.343), with no detectable loss of ersity as a result of indigenous and industrial-scale fishing activity. While there was no evidence for contemporary population structure (AMOVA, p = 0.764), phylogeographic analyses identified two distinct mitochondrial clades that erged approximately 650,000 years ago during the mid-Pleistocene, suggesting the species experienced barriers to gene flow when sea levels dropped over 120 m during previous glacial maxima. An exponential population increase was also observed around 8000 years ago consistent with a post-glacial expansion, which was likely facilitated by increased ocean temperatures and rising sea levels. This study demonstrates that glacial cycles likely played an important role in the demographic history of C. auratus and adds to our growing understanding of how dynamic climatic changes have influenced the evolution of coastal marine species.