How Ancient Humans Survived Without Enough Oxygen

How did ancient humans survive without enough oxygen? And what if the answer is a gene borrowed from an extinct cousin? Climb high enough and every breath feels like drinking air through a straw. For decades, scientists believed our species was the first to survive on the roof of the world. Then a Tibetan monk's jawbone, a cave floor full of ancient DNA, and a single gene called EPAS1 rewrote the story. This video follows the full mystery — from the heavy jawbone found in 1980 at Baishiya Karst Cave, to the proteins that revealed a Denisovan, the DNA hidden in cave dirt, the bharal, yak and woolly rhino bones cracked open for marrow, the "thinner blood" of Tibetan highlanders, and the borrowed stretch of Denisovan DNA that most Tibetans still carry today. And the part nobody can answer yet: did the Denisovans in that cave carry the gene too? By the end, you might never look at a pounding heart on a steep climb the same way again. All research and sources are linked below. ———————————————————— 📚 RESEARCH & SOURCES: ▸ The Xiahe Jawbone — Chen, F. et al. "A late Middle Pleistocene Denisovan mandible from the Tibetan Plateau" (2019, Nature 569: 409–412) https://doi.org/10.1038/s41586-019-11... ▸ Denisovan DNA in Cave Sediment — Zhang, D. et al. "Denisovan DNA in Late Pleistocene sediments from Baishiya Karst Cave on the Tibetan Plateau" (2020, Science 370: 584–587) ▸ What Denisovans Ate — Xia, H. et al. "Middle and Late Pleistocene Denisovan subsistence at Baishiya Karst Cave" (2024, Nature 632: 108–113) https://doi.org/10.1038/s41586-024-07... ▸ Tibetan Blood & the EPAS1 Gene — Beall, C.M. et al. "Natural selection on EPAS1 (HIF2α) associated with low hemoglobin concentration in Tibetan highlanders" (2010, PNAS) https://pmc.ncbi.nlm.nih.gov/articles... ▸ The Borrowed Gene — Huerta-Sánchez, E. et al. "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" (2014, Nature 512: 194–197) ▸ When the Gene Arrived — Zhang, X. et al. "The history and evolution of the Denisovan-EPAS1 haplotype in Tibetans" (2021, PNAS) https://doi.org/10.1073/pnas.2020803118 ———————————————————— PEOPLE MENTIONED IN THIS VIDEO: ▸ Fahu Chen — Geoscientist at the Institute of Tibetan Plateau Research (Chinese Academy of Sciences) who led the 2019 study identifying the Xiahe jawbone as Denisovan. ▸ Dongju Zhang — Archaeologist at Lanzhou University who led the excavations at Baishiya Karst Cave and the search for Denisovan DNA in its sediments. ▸ Frido Welker — Paleoproteomics researcher at the University of Copenhagen who helped identify the jawbone from its proteins and co-led the 2024 study of the cave's animal bones. ▸ Huan Xia — Lanzhou University researcher and first author of the 2024 Nature study of Denisovan subsistence at Baishiya Karst Cave. ▸ Cynthia Beall — Anthropologist at Case Western Reserve University whose research on high-altitude populations showed that Tibetans have lower hemoglobin than lowlanders at the same altitude, linked to the EPAS1 gene. ▸ Emilia Huerta-Sánchez — Population geneticist and lead author of the 2014 study showing that the Tibetan EPAS1 variant looks Denisovan. ▸ Xinjun Zhang — Lead author of the 2021 study estimating that the Denisovan EPAS1 variant entered Tibetan ancestors around 48,700 years ago, with natural selection beginning around 9,000 years ago. ———————————————————— CULTURES & PLACES MENTIONED: ▸ The Denisovans — An extinct human lineage first recognized from a finger bone in Denisova Cave in Siberia. Their DNA survives today in people from Tibet to the Pacific. At Baishiya Karst Cave they left behind a jawbone, a rib, DNA in the soil, stone tools, and thousands of butchered animal bones across more than 100,000 years. ▸ Baishiya Karst Cave — A Buddhist holy site on the northeastern edge of the Tibetan Plateau, 3,280 meters above sea level and about 20 meters above the river below. It holds the earliest known hominin fossil on the plateau, dated to at least 160,000 years ago, and a record of Denisovan life stretching from roughly 160,000 to 45,000 years ago. ▸ Tibetans — Highland people whose bodies respond to thin air with a smaller red blood cell increase than lowlanders show. About 87% carry a Denisovan-like version of the EPAS1 gene, compared with about 9% of Han Chinese in the original survey. ———————————————————— 🎨 Animation by Clark ———————————————————— #humanhistory #ancienthistory #archaeology #denisovans #tibet #highaltitude #humanevolution #prehistory #ancientdna #epas1 #explainer #animation #education