Genomic signatures of high-altitude adaptation and chromosomal polymorphism in geladas

• Published in: Nature ecology & evolution Vol. 6; no. 5; pp. 630 - 643
• Main Authors: Chiou, Kenneth L., Janiak, Mareike C., Schneider-Crease, India A., Sen, Sharmi, Ayele, Ferehiwot, Chuma, Idrissa S., Knauf, Sascha, Lemma, Alemayehu, Signore, Anthony V., D’Ippolito, Anthony M., Abebe, Belayneh, Haile, Abebaw Azanaw, Kebede, Fanuel, Fashing, Peter J., Nguyen, Nga, McCann, Colleen, Houck, Marlys L., Wall, Jeffrey D., Burrell, Andrew S., Bergey, Christina M., Rogers, Jeffrey, Phillips-Conroy, Jane E., Jolly, Clifford J., Melin, Amanda D., Storz, Jay F., Lu, Amy, Beehner, Jacinta C., Bergman, Thore J., Snyder-Mackler, Noah
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2022; Nature Publishing Group
• Subjects: 45; 45/22; 45/23; 631/181/2474; 631/208/182; Acclimatization; Adaptation; Altitude; Amino acids; Animals; Biological and Physical Anthropology; Biomedical and Life Sciences; Chromosomes; Ecology; Evolutionary Biology; Evolutionary genetics; Gene families; Genomes; Genomics; Hemoglobin; High altitude; High-altitude environments; Hypoxia; Indigenous species; Karyotypes; Life Sciences; Low altitude; Monkeys; Oxygen; Oxygenation; Paleontology; Polymorphism; Primates; Theropithecus - physiology; Zoology
• ISSN: 2397-334X; 2397-334X
• DOI: 10.1038/s41559-022-01703-4

Primates have adapted to numerous environments and lifestyles but very few species are native to high elevations. Here we investigated high-altitude adaptations in the gelada ( Theropithecus gelada ), a monkey endemic to the Ethiopian Plateau. We examined genome-wide variation in conjunction with measurements of haematological and morphological traits. Our new gelada reference genome is highly intact and assembled at chromosome-length levels. Unexpectedly, we identified a chromosomal polymorphism in geladas that could potentially contribute to reproductive barriers between populations. Compared with baboons at low altitude, we found that high-altitude geladas exhibit significantly expanded chest circumferences, potentially allowing for greater lung surface area for increased oxygen diffusion. We identified gelada-specific amino acid substitutions in the alpha-chain subunit of adult haemoglobin but found that gelada haemoglobin does not exhibit markedly altered oxygenation properties compared with lowland primates. We also found that geladas at high altitude do not exhibit elevated blood haemoglobin concentrations, in contrast to the normal acclimatization response to hypoxia in lowland primates. The absence of altitude-related polycythaemia suggests that geladas are able to sustain adequate tissue-oxygen delivery despite environmental hypoxia. Finally, we identified numerous genes and genomic regions exhibiting accelerated rates of evolution, as well as gene families exhibiting expansions in the gelada lineage, potentially reflecting altitude-related selection. Our findings lend insight into putative mechanisms of high-altitude adaptation while suggesting promising avenues for functional hypoxia research. Analysing a newly assembled genome of the gelada, an endemic Ethiopian monkey that lives in high altitudes, the authors identify a novel karyotype and genomic elements associated with high-altitude adaptation.