Why Is 2% Of You Not Human?

About two percent of your DNA came from a different human species that went extinct forty thousand years ago. Those fragments are not decoration. They are still helping decide how fast your blood clots, how loudly you feel pain, when your body thinks the day should start, and how hard your immune system swings at a bit of pollen. This is the list of the parts of you a Neanderthal is still running, from a cave in Croatia to an intensive care ward in 2020. And it ends with the part nobody talks about: what natural selection quietly deleted from them, and why not one person alive carries a Neanderthal Y chromosome. 🔔 Subscribe for more videos about ancient humans, human evolution, Neanderthals, prehistoric life, ice age survival and the strange origins of your own body. CHAPTERS 0:00 The 2% in the mirror 0:20 What those pieces still run 0:58 How another species got inside you 1:15 Pääbo and the cave in Croatia 1:54 A window of a few thousand years 2:27 Quick question: are you a night owl? 2:44 Trait one: the clock inside your body 3:08 What the UK Biobank found 3:29 Who the real night owl is 3:51 Trait two: your pain dial 4:14 Carriers feel eight years older 4:32 Why loud pain kept them alive 5:11 Trait three: skin built for an ice age 5:37 The strongest signal in your genome 6:06 Goosebumps and the fur you lost 6:41 Trait four: an immune system that never stands down 7:01 The cheat sheet they handed us 7:23 The bill: allergies and autoimmunity 7:44 Chromosome 3 and severe Covid 8:23 Trait five: blood that closes too fast 8:50 The same blood in an airplane seat 9:15 Trait six: mood, and the cigarette 10:31 The honest part: 2% is not a personality 11:20 A fifth of their genome is still out there 11:46 The deserts in your DNA 12:17 The hybrid children: Oase 1 and Denny 13:01 No Neanderthal Y chromosome. None. 13:27 Their species got audited 14:00 Look in the mirror again 14:28 A question for you SOURCES Green, R. et al. (2010) A Draft Sequence of the Neandertal Genome. Science. The Nobel Prize in Physiology or Medicine 2022: Svante Pääbo. NobelPrize.org. Prüfer, K. et al. (2014) The complete genome sequence of a Neanderthal from the Altai Mountains. Nature. Fu, Q. et al. (2015) An early modern human from Romania with a recent Neanderthal ancestor. Nature. Slon, V. et al. (2018) The genome of the offspring of a Neanderthal mother and a Denisovan father. Nature. Sümer, A. et al. (2024) Earliest modern human genomes constrain timing of Neanderthal admixture. Nature. Iasi, L. et al. (2024) Neanderthal ancestry through time. Science. Zeberg, H., Dannemann, M. et al. (2020) A Neanderthal Sodium Channel Increases Pain Sensitivity in Present-Day Humans. Current Biology. Dannemann, M. et al. (2023) Neanderthal introgression and the human circadian clock. Genome Biology and Evolution. Simonti, C. et al. (2016) The phenotypic legacy of admixture between modern humans and Neandertals. Science. Dannemann, M., Andrés, A. & Kelso, J. (2016) Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors. American Journal of Human Genetics. Zeberg, H. & Pääbo, S. (2020) The major genetic risk factor for severe COVID-19 is inherited from Neanderthals. Nature. Zeberg, H. & Pääbo, S. (2021) A genomic region associated with protection against severe COVID-19 is inherited from Neandertals. PNAS. Sankararaman, S. et al. (2014) The genomic landscape of Neanderthal ancestry in present-day humans. Nature. Vernot, B. & Akey, J. (2014) Resurrecting surviving Neandertal lineages from modern human genomes. Science. Chen, L. et al. (2020) Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals. Cell.