Abstract
The hypoxia adaptation to high altitudes is of considerable interest in the biological sciences. As a breed with adaptability to highland environments, the Tibetan chicken (Gallus gallus domestics), provides a biological model to search for genetic differences between high and lowland chickens. To address mechanisms of hypoxia adaptability at high altitudes for the Tibetan chicken, we focused on the Endothelial PAS domain protein 1 (EPAS1), a key regulatory factor in hypoxia responses. Detected were polymorphisms of EPAS1 exons in 157 Tibetan chickens from 8 populations and 139 lowland chickens from 7 breeds. We then designed 15 pairs of primers to amplify exon sequences by Sanger sequencing methods. Six single nucleotide polymorphisms (SNPs) were detected, including 2 missense mutations (SNP3 rs316126786 and SNP5 rs740389732) and 4 synonymous mutations (SNP1 rs315040213, SNP4 rs739281102, SNP6 rs739010166, and SNP2 rs14330062). There were negative correlations between altitude and mutant allele frequencies for both SNP6 (rs739010166, r = 0.758, p<0.001) and SNP3 (rs316126786, r = 0.844, P<0.001). We also aligned the EPAS1 protein with ortholog proteins from diverse vertebrates and focused that SNP3 (Y333C) was a conserved site among species. Also, SNP3 (Y333C) occurred in a well-defined protein domain Per-AhR-Arnt-Sim (PAS domain). These results imply that SNP3 (Y333C) is the most likely casual mutation for the high-altitude adaption in Tibetan chicken. These variations of EPAS1 provide new insights into the gene’s function.
Highlights
Low oxygen is one of the more severe environmental challenges for animals living in high-altitude regions such as the Tibetan Plateau, where the average altitude is above 4000 m
To detect single nucleotide polymorphisms (SNPs) sites which had putative associations with a high-altitude environment, we focused on genotypes which difference (P < 0.05) between Tibetan chickens (TC) and lowland chickens (LC)
The same tendency was found in SNP6 (Fig 3C). These results suggested that the frequencies of SNP3 and SNP6 in Endothelial PAS domain protein 1 (EPAS1) decreased with the elevation of altitude
Summary
Low oxygen is one of the more severe environmental challenges for animals living in high-altitude regions such as the Tibetan Plateau, where the average altitude is above 4000 m. The partial pressure of oxygen at 4000 m is approximately 50% of that at sea-level, and the hypoxia imposes severe constraints on aerobic metabolism and leading to high-altitude illness[1, 2][3] and the mechanisms of hypoxic adaptation [4]. The Tibetan chicken (Gallus gallus; TC) is an aboriginal breed found in the QinghaiTibetan Plateau (QTP), where the altitude range from 2200 to 4100 m. They are smaller, mature at older ages and lay smaller eggs than breed at lower altitude (Table A in S1 File). It is obviously that TC process unique physiological properties and there provide a model for studying genetic mechanisms of hypoxia adaptation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
