2026-10-07T23:48:20Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33990904 2026-09-24T21:00:17Z category_24250 category_24271 category_24280 category_24256 item_type_3 month_year_09_2026

Molas have mighty mitochondria: intensified purifying selection on mtDNA despite presumed “low-energy” lifestyles in ocean sunfishes (family Molidae) Justin Havird (2812975) Biological adaptation Phylogeny and comparative analysis Evolutionary biology not elsewhere classified Evolutionary ecology energetics dN/dS ratios mitochondria environmental adaptation molecular evolution mitonuclear ecology <p dir="ltr">Dataset accompanying related publication in Evolution:</p><p><br></p><p dir="ltr"><br></p><p dir="ltr">Ocean sunfish (family Molidae) are often perceived as “low-energy” drifters composed largely of connective tissue with noticeably missing fins and even cited as “mistakes” of natural selection. Because locomotory capacity has been identified as a driver of evolution in animal mitochondrial genomes (mtDNA), ocean sunfish are expected to show signatures of relaxed selection on mtDNA compared to closely related, more energetic species. Contrary to expectations, ocean sunfish showed lower <i>d</i>_N/<i>d</i>_S ratios (the ratio of non-synonymous to synonymous substitution rates) in all mitochondrial-encoded genes and further analyses strongly suggest this is due to increased purifying selection on mtDNA within Molidae. Population genetic data also support more intense selection on ocean sunfish mtDNA. These results agree with recent studies recharacterizing ocean sunfish as active swimmers with a complex lifestyle including extreme vertical migrations, behavioral thermoregulation, and extreme fecundity. Finally, across 64 diverse fishes, mtDNA evolutionary rates did not correlate with swimming speed. More broadly, this study highlights how predicting selection on mitochondrial genes is not straightforward. Assuming different selective pressures on mtDNA given locomotion or different perceived “lifestyles” may be an oversimplification, analogous to regarding an unusual species as an evolutionary “mistake”.</p> 2026-09-24T21:00:17Z Dataset Dataset 10.6084/m9.figshare.33990904.v1 https://figshare.com/articles/dataset/Molas_have_mighty_mitochondria_intensified_purifying_selection_on_mtDNA_despite_presumed_low-energy_lifestyles_in_ocean_sunfishes_family_Molidae_/33990904 CC BY 4.0