Markhor-derived introgression of PAPSS2 confers high-altitude adaptability in Tibetan goats

Understanding the genetic mechanism of how animals adapt to extreme environments is fundamental to unriddle the relationship between molecular evolution and continuous climate change. After domestication, goats have developed strong adaptation to various environments, including harsh conditions at high-altitudes with low temperature and reduced oxygen concentrations. Here, we utilized 331 genomes of goats living at varying altitudes (high >3,000 m above sea level and low <1,200 m) as well as wild caprid species to precisely dissect genetic determinants underlying the adaptation to high altitudes on the Qinghai-Tibetan Plateau (QTP). Population genomic analyses combined with genome-wide association testing revealed that the PAPSS2 locus confers adaptability to high altitudes in Tibetan goats. Additionally, this gene harbours significant signatures of interspecies introgression from a wild caprid species, markhor (Capra falconeri). We further demonstrated a functional role for PAPSS2 in response to hypoxia using PAPSS2-deficient cells. In conclusion, our results suggest a hitherto unknown contribution of PAPSS2 to high-altitude adaptation and showed that interspecific introgression contributed to the adaptation of goats to the harsh conditions at the Tibetan Plateau

Taxonomic and functional adaption of the gastrointestinal microbiome of goats kept at high altitude (4800 m) under intensive or extensive rearing conditions

The gut microbiota composition is influenced by the diet as well as the environment in both wild and domestic animals. We studied the effects of two feeding systems on the rumen and hindgut microbiome of semi-feral Tibetan goats kept at high altitude (∼4800 m) using 16S rRNA gene and metagenomic sequencing. Intensive drylot feeding resulted in significantly higher zootechnical performance, narrower ruminal acetate: propionate ratios and a drop in the average rumen pH at slaughter to ∼5.04. Hindgut microbial adaption appeared to be more diverse in the drylot group suggesting a higher influx of undegraded complex non-starch polysaccharides from the rumen. Despite their higher fiber levels in the diet, grazing goats exhibited lower counts of Methanobrevibacter and genes associated with the hydrogenotrophic methanogenesis pathway, presumably reflecting the scarce dietary conditions (low energy density) when rearing goats on pasture from extreme alpine environments. These conditions appeared to promote a relevant abundance of bacitracin genes. In parallel, we recognized a significant increase in the abundance of antibiotic resistance genes in the digestive tracts of drylot animals. In summary, this study provides a deeper insight into the metataxonomic and functional adaption of the gastrointestinal microbiome of goats subject to intensive drylot and extensive pasture rearing conditions at high altitud