Molecular cloning and characterization of hemoglobin alpha and beta 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 3,000-5,000 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 alpha and beta chains have been described. Compared with human Hb, alterations in important regions can be noted: alpha111 Ala-->Asn, beta35 Tyr-->Phe, beta112 Cys-->Val, beta115 Ala-->Ser, and beta125 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.