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

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

Kruger National Park

Congreso; Seventh International Barcode of Life Conference; 2017

African Centre for DNA Barcoding (ACDB) y University of Johannesburg (UJ)

Background: Adaptation to hypoxic highlands has been widely studiedin diverse organisms, mainly by analyzing genetic and aminoacidic changes in haemoglobin and their physiological consequences.In spite of the relevant role of mitochondrial genes in the cellularrespiratory process, their adaptation to high altitude has been lessstudied. Moreover, contrasting results have been found, with apparentadaptation present only in some high-altitude species. Broadanalyses are therefore needed to establish general patterns of mitochondrialadaptation to hypoxic environments. In this context, andtaking advantage of the large-scale genetic library generated by theBarcode of Life project, we studied COI adaptation to high altitude inbirds in the Americas. Results: Over 22 000 COI sequences fromaround 2000 avian species from the American Continent were retrievedfrom the Barcode of Life Data System (BOLD). Using a completephylogeny of the birds of the World, we classified 155 pairs of sisterspecies into highland?lowland, highland?highland, and lowland?lowland species pairs to compare their COI sequences (2300 sequencesused in total). Even though we did not find evidence of a generalizedadaptation to high altitude in COI, there was a tendency towards morechanges in amino acids and a higher proportion of sister species withdifferences in their amino acids in highland?lowland and highland?highland species pairs than in lowland?lowland species pairs. We alsoanalyzed the amino acids that did differ between highland and lowlandspecies to assess their position and whether their properties differed to assess whether the modification could affect the proteinstructure and function. Significance: This is the first large-scale analysisof mitochondrial adaptation to high altitude in any taxonomicgroup, and the results suggest that the adaptation of COI to hypoxichighlands in birds is idiosyncratic. This study constitutes an exampleof how DNA barcode libraries allow diverse large-scale analyses beyondspecies identification and discovery