Molecular cloning and characterization of hemoglobin α and β chains from plateau pika (Ochotona curzoniae) living at high altitude

Hemoglobin (Hb) plays an important role in oxygen transfer from lung to tissues. Possession of a Hb with high oxygen affinity helps highland animals to adapt to high altitude, has been studied profoundly. Plateau pika (Ochotona curzoniae), a native species living at 3000–5000 m above sea level on Qinghai-Tibet Plateau, is a typical hypoxia and low temperature tolerant mammal. To investigate the possible mechanisms of plateau pika Hb in adaptation to high altitude, the complete cDNA and amino acid sequences of plateau pika hemoglobin α and β chains have been described. Compared with human Hb, alterations in important regions can be noted: α111 Ala→Asn, β35 Tyr→Phe, β112 Cys→Val, β115 Ala→Ser, and β125 Pro→Gln. Phylogenetic analysis of alpha and beta chains shows that plateau pika is closer to rabbit than to other species. This study provides essential information for elucidating the possible roles of hemoglobin in adaptation to extremely high altitude in plateau pika.