February 19, 2018, University of Nebraska-Lincoln
On the Himalayan-enveloped Tibetan Plateau and the Altiplano plateau of South America – the world's two highest tabletops – a select few bird species survive on 35 to 40 percent less oxygen than at sea level.
All extreme-altitude birds have evolved especially efficient systems for delivering that precious oxygen to their tissues. But a new study led by the University of Nebraska-Lincoln and Chinese Academy of Sciences has found that these birds often evolved different blueprints for assembling the proteins – hemoglobins – that actually capture oxygen.
Published in the Proceedings of the National Academy of Sciences, the study found that many species from the two plateaus underwent different mutations to produce the same result: hemoglobins more adept at snaring oxygen from the lungs before sharing it with the other organs that depend on it.
Those mutational differences often emerged even among closely related species residing on the same plateau, the study reported.
"You could imagine, just because of the different ancestral starting points, that the Tibetan birds maybe all went one (mutational) route, and the Andean birds typically did things a different way," said co-author Jay Storz, Susan J. Rosowski Professor of Biological Sciences at Nebraska. "But that's not what we saw. Across the board, there weren't really any region-specific patterns.
"In both cases, it seems like there were many different ways of evolving a similar alteration of protein function."