Repository logo

Browsing by Author "Wright, David K."

Now showing 1 - 3 of 3
  • Ancient DNA and deep population structure in sub-Saharan African foragers
    Publication . Lipson, Mark; Sawchuk, Elizabeth A.; Thompson, Jessica C.; Oppenheimer, Jonas; Tryon, Christian A.; Ranhorn, Kathryn L.; de Luna, Kathryn M.; Sirak, Kendra A.; Olalde, Iñigo; Ambrose, Stanley H.; Arthur, John W.; Arthur, Kathryn J. W.; Ayodo, George; Bertacchi, Alex; Cerezo-Román, Jessica I.; Culleton, Brendan J.; Curtis, Matthew C.; Davis, Jacob; Gidna, Agness O.; Hanson, Annalys; Kaliba, Potiphar; Katongo, Maggie; Kwekason, Amandus; Laird, Myra F.; Lewis, Jason; Mabulla, Audax Z. P.; Mapemba, Fredrick; Morris, Alan; Mudenda, George; Mwafulirwa, Raphael; Mwangomba, Daudi; Ndiema, Emmanuel; Ogola, Christine; Schilt, Flora; Willoughby, Pamela R.; Wright, David K.; Zipkin, Andrew; Pinhasi, Ron; Kennett, Douglas J.; Manthi, Fredrick Kyalo; Rohland, Nadin; Patterson, Nick; Reich, David; Prendergast, Mary E.
    Multiple lines of genetic and archaeological evidence suggest that there were major demographic changes in the terminal Late Pleistocene epoch and early Holocene epoch of sub-Saharan Africa(1-4). Inferences about this period are challenging to make because demographic shifts in the past 5,000 years have obscured the structures of more ancient populations(3,5). Here we present genome-wide ancient DNA data for six individuals from eastern and south-central Africa spanning the past approximately 18,000 years (doubling the time depth of sub-Saharan African ancient DNA), increase the data quality for 15 previously published ancient individuals and analyse these alongside data from 13 other published ancient individuals. The ancestry of the individuals in our study area can be modelled as a geographically structured mixture of three highly divergent source populations, probably reflecting Pleistocene interactions around 80-20 thousand years ago, including deeply diverged eastern and southern African lineages, plus a previously unappreciated ubiquitous distribution of ancestry that occurs in highest proportion today in central African rainforest hunter-gatherers. Once established, this structure remained highly stable, with limited long-range gene flow. These results provide a new line of genetic evidence in support of hypotheses that have emerged from archaeological analyses but remain contested, suggesting increasing regionalization at the end of the Pleistocene epoch. DNA analysis of 6 individuals from eastern and south-central Africa spanning the past approximately 18,000 years, and of 28 previously published ancient individuals, provides genetic evidence supporting hypotheses of increasing regionalization at the end of the Pleistocene.
    2022Journal article Open Access Show more
  • Early human impacts and ecosystem reorganization in southern-central Africa
    Publication . Thompson, Jessica C.; Wright, David K.; Ivory, Sarah J.; Choi, Jeong-Heon; Nightingale, Sheila; Mackay, Alex; Schilt, Flora; Otárola-Castillo, Erik; Mercader, Julio; Forman, Steven L.; Pietsch, Timothy; Cohen, Andrew S.; Arrowsmith, J. Ramón; Welling, Menno; Davis, Jacob; Schiery, Benjamin; Kaliba, Potiphar; Malijani, Oris; Blome, Margaret W.; O’Driscoll, Corey A.; Mentzer, Susan M.; Miller, Christopher; Heo, Seoyoung; Choi, Jungyu; Tembo, Joseph; Mapemba, Fredrick; Simengwa, Davie; Gomani-Chindebvu, Elizabeth
    Modern Homo sapiens engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an early, pre-agricultural anthropogenic landscape.
    2021Journal article Open Access Show more
  • Hunter-gatherer environments at the Late Pleistocene sites of Mwanganda's Village and Bruce, northern Malawi
    Publication . Schilt, Flora; Miller, Christopher E.; Wright, David K.; Mentzer, Susan M.; Mercader, Julio; Moss, Patrick; Choi, Jeong-Heon; Siljedal, Gunnar; Clarke, Siobhán; Mwambwiga, Aloyce; Thomas, Kelly; Barbieri, Alvise; Kaliba, Potiphar; Gomani-Chindebvu, Elizabeth; Thompson, Jessica C.
    Mwanganda's Village (MGD) and Bruce (BRU) are two open-air site complexes in northern Malawi with deposits dating to between 15 and 58 thousand years ago (ka) and containing Middle Stone Age (MSA) lithic assemblages. The sites have been known since 1966 and 1965, respectively, but lacked chronometric and site formation data necessary for their interpretation. The area hosts a rich stone artifact record, eroding from and found within alluvial fan deposits exhibiting poor preservation of organic materials. Although this generally limits opportunities for site-based environmental reconstructions, MGD and BRU are located at the distal margins of the alluvial fan, where lacustrine lagoonal deposits were overprinted by a calcrete paleosol. This has created locally improved organic preservation and allowed us to obtain ecological data from pollen, phytoliths, and pedogenic carbonates, producing a regional-to site-scale environmental context for periods of site use and abandonment. Here, we integrate the ecological data into a detailed site formation history, based on field observations and micromorphology, supplemented by cathodoluminescence microscopy and mu-XRF. By comparing local, on-site environmental proxies with more regional indicators, we can better evaluate how MSA hunter-gatherers made decisions about the use of resources across the landscape. Our data indicate that while tree cover similar to modern miombo woodland and evergreen gallery forest prevailed at most times, MSA hunter-gatherers chose more locally open environments for activities that resulted in a lithic artifact record at multiple locations between 51 and 15 ka.(C) 2022 The Authors. Published by Elsevier Ltd.
    2022Journal article Open Access Show more