Better understanding how the truffles reproduce has major implications for farmers, chefs, and foodies enamored with the expensive, pungent fungus.
Image courtesy of Shutterstock/Vitalina Rybakova.
New Research In
Physical Sciences
Featured Portals
Articles by Topic
Biological Sciences
Featured Portals
Articles by Topic
Edited by Ofer Bar-Yosef, Harvard University, Cambridge, MA, and approved July 27, 2011 (received for review June 13, 2011)
Abstract
A long-debated question concerns the fate of archaic forms of the genus Homo: did they go extinct without interbreeding with anatomically modern humans, or are their genes present in contemporary populations? This question is typically focused on the genetic contribution of archaic forms outside of Africa. Here we use DNA sequence data gathered from 61 noncoding autosomal regions in a sample of three sub-Saharan African populations (Mandenka, Biaka, and San) to test models of African archaic admixture. We use two complementary approximate-likelihood approaches and a model of human evolution that involves recent population structure, with and without gene flow from an archaic population. Extensive simulation results reject the null model of no admixture and allow us to infer that contemporary African populations contain a small proportion of genetic material (≈2%) that introgressed ≈35 kya from an archaic population that split from the ancestors of anatomically modern humans ≈700 kya. Three candidate regions showing deep haplotype divergence, unusual patterns of linkage disequilibrium, and small basal clade size are identified and the distributions of introgressive haplotypes surveyed in a sample of populations from across sub-Saharan Africa. One candidate locus with an unusual segment of DNA that extends for >31 kb on chromosome 4 seems to have introgressed into modern Africans from a now-extinct taxon that may have lived in central Africa. Taken together our results suggest that polymorphisms present in extant populations introgressed via relatively recent interbreeding with hominin forms that diverged from the ancestors of modern humans in the Lower-Middle Pleistocene.
Footnotes
- ↵1To whom correspondence should be addressed. E-mail: mfh{at}email.arizona.edu.
Author contributions: M.F.H., A.E.W., F.L.M., J.C.W., and J.D.W. designed research; A.E.W. and J.D.W. performed research; A.E.W., F.L.M., J.C.W., and J.D.W. analyzed data; and M.F.H., A.E.W., F.L.M., J.C.W., and J.D.W. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1109300108/-/DCSupplemental.
Genetic evidence for archaic admixture in Africa
More Articles of This Classification
Biological Sciences
Related Content
Cited by...
- Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago
- Living in an adaptive world: Genomic dissection of the genus Homo and its immune response
- A demographic perspective on the Middle to Later Stone Age transition from Nasera rockshelter, Tanzania
- Ancient DNA and human history
- Model-based analyses of whole-genome data reveal a complex evolutionary history involving archaic introgression in Central African Pygmies
- Whole-genome sequence analyses of Western Central African Pygmy hunter-gatherers reveal a complex demographic history and identify candidate genes under positive natural selection
- Origins and Evolution of Hepatitis B Virus and Hepatitis D Virus
- Ancient Ethiopian genome reveals extensive Eurasian admixture in Eastern Africa
- Worldwide Population Structure, Long-Term Demography, and Local Adaptation of Helicobacter pylori
- Genetic Variation and Adaptation in Africa: Implications for Human Evolution and Disease
- Resurrecting Surviving Neandertal Lineages from Modern Human Genomes
- Higher Levels of Neanderthal Ancestry in East Asians than in Europeans
- Genomic Variation in Seven Khoe-San Groups Reveals Adaptation and Complex African History
- Longer time scale for human evolution
- Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins
- Human Evolution Out of Africa: The Role of Refugia and Climate Change
Similar Articles
You May Also be Interested in
PNAS QnAs with NAS foreign associate and metabolic engineer Sang Yup Lee
Researchers report a species of early bird with a combination of bird-like and dinosaur-like bone morphologies, and the structure of the bird’s shoulder girdle highlights the role of developmental plasticity in the early evolution of birds, according to the authors.
A study suggests that the herbicide glyphosate disrupts bee gut microbiota, increasing bees’ susceptibility to pathogens, and that glyphosate’s effects may contribute to the largely unexplained increase in honey bee colony mortality.
Image courtesy of Vivian Abagiu (The University of Texas at Austin, Austin, TX).
A study finds that a fragment of an ancient retrovirus, integrated in human ancestors before the emergence of Neanderthals, is found more frequently in people who contracted HIV and hepatitis C through intravenous drug use, compared with control populations.
Image courtesty of Pixabay/typographyimages.
