Different Mechanisms For High Altitude Adaptation To Hypoxia: Genomics Of The Highaltitude Yak and The Highealtitude-Subterranean Zokor In The Qinghai-Tibet Plateau

Due to the unique climate and environmental conditions such as hypoxia, cold and strong ultraviolet, the Qinghai-Tibet plateau has been regarded as an ideal place to investigate high-altitude adaptation. In order to survive under such extreme environment, animals live on the Qinghai-Tibet plateau have changed dramatically on both phenotype and genotype. Previous analyses revealed that gene families related to hypoxia stress in yak (Bos grunniens) have gained extra copies compared to that in cattle. Positively selected genes (PSGs) and rapidly evolving genes in the yak lineage were also found to be significantly enriched in functional categories and pathways related to hypoxia. However, different species may not necessarily possess the same mechanism to adapt to the certain environment. To further reveal the divergent and convergent pattern in high-altitude adaptation between different species we sequenced five organs' (brain, heart, kidney, liver and spleen) transcriptome of plateau zokor (Eospalax Baileyi), a blind subterranean rodent lives at an altitude of 2800 meters to 4300 meters. By genomic comparisons between the closely related low-altitude mouse we found positively selected genes in plateau zokor that are significantly enriched in the Gene Ontology terms such as "angiogenesis" and " ion transport" . The different pattern of zokor PSGs implies different mechanisms for high altitude adaptation. Meanwhile, common mechanisms may also exist since we identified 118 convergent genes in plateau zokor and yak which are significantly more than what can be predicted from random generation.