VERDICT: TRUE The viral TikTok claim — "In 2010 Scientists Found DNA From a Third Human Species Nobody Knew Existed" — is substantively accurate. In December 2010, an international team led by Svante Pääbo (Max Planck Institute) and David Reich (Harvard) sequenced the genome of a previously unknown archaic hominin group from a finger bone found in Denisova Cave, Siberia. This group, named the "Denisovans," was neither Neanderthal nor modern human, and its DNA was found in present-day Melanesian populations. The core facts of the claim check out. Two claim-linked findings: 1. The 2010 study sequenced the genome of an archaic hominin to ~1.9-fold coverage from a finger bone in Denisova Cave, and designated this previously unknown population "Denisovans," noting it "shares a common origin with Neanderthals" but has "an evolutionary history distinct from Neanderthals and modern humans." The data showed this group contributed 4–6% of its genetic material to present-day Melanesians. 2. The UC Berkeley/NSF press release confirms researchers "identified a previously unknown population of early humans, whom the researchers call 'Denisovans'" — a group that was "neither Neanderthal nor a modern human" — based on DNA from a finger bone of a 5–10-year-old girl, plus a tooth whose shape "falls outside normal tooth variation typically seen in Neanderthals and modern humans." Primary sources cited (peer-reviewed journal, university, and government domains): 1. Reich, D. et al. "Genetic history of an archaic hominin group from Denisova Cave in Siberia," Nature 468, 1053–1060 (2010). https://www.nature.com/articles/nature09710 2. UC Berkeley Research / National Science Foundation, "Third Human Species Discovered in Siberian Cave" (Dec 22, 2010). https://vcresearch.berkeley.edu/news/third-human-species-discovered-siberian-cave 3. PubMed / NIH (NCBI), PMID 21179161 (same peer-reviewed study, government domain). https://pubmed.ncbi.nlm.nih.gov/21179161/ One minor caveat for precision: the original authors deliberately "refrain from any formal Linnaean taxonomic designations that would indicate species or subspecies status" for the Denisovans, so "third human species" is a popular simplification rather than a formal taxonomic claim. However, the substance — that scientists in 2010 discovered DNA from a previously unknown archaic human group — is fully supported by the primary literature.