Milk is a major food of global economic importance, and its consumption is regarded as a classic example of gene-culture evolution. Humans have exploited animal milk as a food resource for at least 8500 years, but the origins, spread, and scale of dairying remain poorly understood. Indirect lines of evidence, such as lipid isotopic ratios of pottery residues, faunal mortality profiles, and lactase persistence allele frequencies, provide a partial picture of this process; however, in order to understand how, where, and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their dairy livestock. Here we report the first direct evidence of milk consumption, the whey protein β-lactoglobulin (BLG), preserved in human dental calculus from the Bronze Age (ca. 3000 BCE) to the present day. Using protein tandem mass spectrometry, we demonstrate that BLG is a species-specific biomarker of dairy consumption, and we identify individuals consuming cattle, sheep, and goat milk products in the archaeological record. We then apply this method to human dental calculus from Greenland's medieval Norse colonies, and report a decline of this biomarker leading up to the abandonment of the Norse Greenland colonies in the 15th century CE.

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Gigantopithecus blacki was a giant hominid that inhabited densely forested environments of Southeast Asia during the Pleistocene 1. Its evolutionary relationships to other great ape species, and their divergence during the Middle and Late Miocene (16-5.3 Mya), remains disputed 2,3. Hypotheses regarding relationships between Gigantopithecus and extinct and extant hominids are difficult to substantiate because of its highly derived dentognathic morphology and the absence of cranial and post-cranial remains 1,3-6. Therefore, proposed hypotheses on the phylogenetic position of Gigantopithecus among hominids have been wide-ranging, but none have received independent molecular validation. We retrieved dental enamel proteome sequences from a 1.9 million years (Mya) old Gigantopithecus blacki molar found in Chuifeng Cave, China 7,8. The thermal age of these protein sequences is approximately five times older than any previously published mammalian proteome or genome. We demonstrate that Gigantopithecus is a sister clade to orangutans (genus Pongo) with a common ancestor about 10-12 Mya, implying that the Gigantopithecus divergence from Pongo is part of the Miocene radiation of great apes. Additionally, we hypothesize that the expression of alpha-2-HS-glycoprotein (AHSG), which has not been observed in enamel proteomes previously, had a role in the biomineralization of the thick enamel crowns that characterize the large molars in the genus 9,10. The survival of an Early Pleistocene dental enamel proteome in the subtropics further expands the scope of palaeoproteomic analysis into geographic areas and time periods previously considered incompatible with genetic preservation. Gigantopithecus blacki is an extinct, potentially giant hominid species that once inhabited Asia. It was first discovered and identified by von Koenigswald in 1935 when he described an isolated tooth that he found in a Hong Kong drugstore 11. The entire Gigantopithecus blacki fossil record, dated between the Early Pleistocene (~2.0 Mya) and the late Middle Pleistocene (~0.3 Mya 12), includes thousands of teeth and four partial mandibles from subtropical Southeast Asia 1,13,14. All the known Gigantopithecus blacki localities are situated in southern China, stretching from Longgupo Cave, just south of the Yangtze River, to the Xinchong Cave on Hainan Island, and, possibly, into northern Vietnam and Thailand 15,16. To address the evolutionary relationships between Gigantopithecus and extant hominoids, we performed protein extractions on dentine and enamel samples of a single molar (CF-B-16) found in Chuifeng Cave, China, that is morphologically assigned to Gigantopithecus blacki 7,8. The site is dated using multiple approaches to 1.9±0.2 Mya (Extended Data Figs. 1, 2). Enamel and dentine samples were processed using recently established digestion-free protocols optimized for extremely degraded ancient proteomes 17 (Methods). Enamel demineralization was replicated using two different acids, trifluoroacetic acid (TFA) and hydrochloric acid (HCl). Welker et ...