Large-scale assessment of mitochondrial adaptation to high altitude in birds

ESTALLES, CECILIA; LAVINIA OBLANCA PABLO DAMIÁN; TUBARO PABLO LUIS; LIJTMAER DARÍO A.

Puerto Iguazú

Congreso; Ornithological Congress of the Americas; 2017

Aves Argentinas, Sociedade Brasileira de Ornitologia, Association of Field Ornithologists

Adaptation to hypoxic highlands has been widely studied in birds, mainly analyzing molecular and physiological changes in haemoglobin. Although mitochondrial genes participate in the cellular respiratory process, their adaptive role to high altitude has been much less studied and contrasting results have been found. Therefore, broad analyses are needed to establish general patterns of mitochondrial adaptation to hypoxic environments. In this context, using a large-scale genetic library we studied COI adaptation to high altitude in the birds in the Americas. Over 22,000 COI sequences from around 2,000 avian species from the American Continent were retrieved. Using a complete phylogeny of the birds of the World we classified 155 pairs of sister species into highland-lowland, highland-highland and lowland-lowland species pairs to compare their COI sequences. Even though we did not find evidence of a generalized adaptation to high altitude in COI, there was a tendency towards more changes in amino acids and a higher proportion of sister species with differences in their amino acids in highland-lowland and highland-highland species pairs than in lowland-lowland species pairs. We also analyzed the amino acids that did differ between highland and lowland species to assess their position and whether their properties differed, to study whether the modification could affect the protein structure and function. This is the first large-scale analysis of mitochondrial adaptation to high altitude in birds, and the results suggest that the adaptation of COI to hypoxic highlands is idiosyncratic.