Hummingbirds in flight exhibit the highest metabolic rate of all vertebrates. The bioenergetic requirements associated with hovering flight raise the possibility of positive selection upon proteins encoded by hummingbird mitochondrial DNA. Here, we have identified a non-conservative change within the mitochondria-encoded cytochrome c oxidase subunit I (COI) that is fixed within hummingbirds, yet exceedingly rare among other metazoans. This unusual change can also be identified in several nectarivorous hovering insects, hinting at convergent evolution linked to diet or mode of flight over ~800 million years. We performed atomistic molecular dynamics simulations using bovine and hummingbird COI models, thereby bypassing experimental limitations imposed by the inability to modify mtDNA in a site-specific manner. Intriguingly, our findings suggest that COI amino acid position 153 provides control over the hydration and activity of a key proton channel. We discuss potential phenotypic outcomes for the hummingbird that are linked to this intriguing instance of positive selection upon the mitochondrial genome.
|Status||Insänt - 28 okt 2019|
|MoE-publikationstyp||D4 Publicerad utvecklings- eller forskningsrapport eller studie|