Jay F. Storz from the University of Nebraska and colleagues from Aarhus University in Denmark, the University of Illinois, the University of California at Berkeley, and the University of New Mexico are the first to reveal how hummingbirds that reside at high altitudes are able to retain sufficient oxygen for life in the Dec. 2, 203, edition of the journal Proceedings of the National Academy of Sciences.
The researchers investigated the structure of hemoglobin in several species of hummingbirds that are native to the Andes. Each species lived at different elevations in the Andes.
Each species of hummingbird revealed a hemoglobin molecule that had a different affinity with oxygen. Hummingbirds that normally live at high altitudes had hemoglobin that entrapped and held oxygen longer than lower altitude birds.
The researchers used computer simulation to recreate the most ancient ancestors of present day Andean hummingbirds and found that the locus of differentiation in the hummingbird hemoglobin was a mutation in two amino acids.
The scientists further discovered that this hemoglobin adaptation occurred independently in each species of hummingbird. All Andean hummingbirds do not have a common ancestor. The modification in hummingbird hemoglobin affinity with oxygen varies with elevation.
The research also indicates that the molecular basis of adaptive evolution may be more predictable than previously thought.