bims-humivi Biomed News
on Human mito-nuclear genetic interplay
Issue of 2025–11–30
two papers selected by
Mariangela Santorsola, Università di Pavia
  1. Haplodiploidy accelerates mitogenome evolution in insects.
  2. Biogeographic Structure and Mitonuclear Discordance Reveal Cryptic Diversity in Pacific Herring (Clupea pallasii).
  1. Proc Biol Sci. 2025 Nov;292(2059): 20251813
    Haplodiploidy accelerates mitogenome evolution in insects.
    Avas Pakrashi, Ken A Thompson, Paul D N Hebert.
      Rates of mitogenome evolution differ among animal lineages, and this variation has been linked to life history, to ecological traits and-potentially-to the sex-determination system. Insects are a compelling model for examining the latter factor because haplodiploid (HD) has evolved on multiple occasions from a diplodiploid (DD) ancestral state. We tested for rate differences between DD and HD taxa by examining sequence change in a sentinel segment of the mitogenome, the 658 bp barcode region of the cytochrome c oxidase subunit I (COI) gene. Specifically, we investigated if amino acid substitutions and indels are more frequent in HD than DD lineages by inspecting COI sequences from over 86 000 BINs (a species proxy) representing 783 insect families and 26 orders. Among them, 10 lineages, varying in rank from tribe to order, are HD. Our analysis, which accounts for phylogeny, indicates that HD lineages have higher rates (1.7×) of amino acid substitution, higher Ka/Ks (3.5×) and far more indels than DD taxa. While our results demonstrate that HD accelerates mitogenome evolution, future work is needed to clarify its mechanistic basis. We hypothesize that HD facilitates positive selection for mitochondrial mutations which encode proteins that interact with nuclear gene products. Such coevolutionary interactions should be facilitated because recessive mutations in the nuclear genome are fully exposed to selection in males of the HD but not the DD lineages.
    Keywords:  COI; DNA barcoding; mito-nuclear interactions; molecular evolution; ploidy; rate acceleration
    DOI:  https://doi.org/10.1098/rspb.2025.1813
  2. Ecol Evol. 2025 Nov;15(11): e72452
    Biogeographic Structure and Mitonuclear Discordance Reveal Cryptic Diversity in Pacific Herring (Clupea pallasii).
    Laura E Timm, Sydney A Almgren, J Andrés López, Jessica R Glass.
      Forage fishes are biological drivers throughout the Pacific Ocean, from the Arctic to nearly subtropical latitudes. As a critical trophic link, the health and stability of Pacific herring (Clupea pallasii) populations have implications for other marine species, including several targeted by large, productive fisheries. Previous research has indicated marked divergence between Pacific herring in the Bering Sea and the Gulf of Alaska. Seeking to localize this biogeographic break, we generated low-coverage whole genome resequencing data for 120 Pacific herring from seven sites across the northern Gulf of Alaska and the eastern Bering Sea and Aleutian Islands. Single nucleotide polymorphisms across the mitogenome (267) and nuclear genome (~5.6 million) corroborate a biogeographic break in Pacific herring along the Alaska Peninsula and Aleutian Islands, as far west as Unalaska. We identified two distinct populations: one exists along the northern coasts of the Aleutian Islands and in the eastern Bering Sea; the other occupies the southern edge of the Aleutians and the Gulf of Alaska. Two mitochondrial haplogroups co-occurring across the Gulf of Alaska suggest secondary contact between two populations, likely representing glacial refugia. Our results underscore the importance of geological events to contextualize the diversification of forage fish species.
    Keywords:  Bering Sea; Gulf of Alaska; forage fish; low‐coverage whole genome resequencing; population genomics
    DOI:  https://doi.org/10.1002/ece3.72452
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