Suchergebnisse

Humans have more copies of amylase genes than other primates. It is still poorly understood, however, when the copy number expansion occurred and whether its spread was enhanced by selection. Here we assess amylase copy numbers in a global sample of 480 high coverage genomes and find that regions flanking the amylase locus show notable depression of genetic diversity both in African and non-African populations. Analysis of genetic variation in these regions supports the model of an early selective sweep in the human lineage after the split of humans from Neanderthals which led to the fixation of multiple copies of AMY1 in place of a single copy. We find evidence of multiple secondary losses of copy number with the highest frequency (52%) of a deletion of AMY2A and associated low copy number of AMY1 in Northeast Siberian populations whose diet has been low in starch content. ; This research was supported by European Research Council Starting Investigator grant FP7-261213 (T.K., C.E.I., L.P., T.E.), Estonian Research Infrastructure Roadmap grant no. 373 3.2.0304.11-0312, the European Union European Regional Development Fund Centre of Excellence in Genomics to the Estonian Biocentre and Estonian Institutional Research grant IUT24-1 (T.K., L.S., G.H., M.M. and R.V.); French Ministry of Foreign and European Affairs and French ANR grant number ANR-14-CE31-0013-01 (F.-X.R.); Program of the RAS Presidium "Basic research for the development of the Russian Arctic" (B.M.).

European populations display low genetic differentiation as the result of long-term blending of their ancient founding ancestries. However, it is unclear how the combination of ancient ancestries related to early foragers, Neolithic farmers, and Bronze Age nomadic pastoralists can explain the distribution of genetic variation across Europe. Populations in natural crossroads like the Italian peninsula are expected to recapitulate the continental diversity, but have been systematically understudied. Here, we characterize the ancestry profiles of Italian populations using a genome-wide dataset representative of modern and ancient samples from across Italy, Europe, and the rest of the world. Italian genomes capture several ancient signatures, including a non-steppe contribution derived ultimately from the Caucasus. Differences in ancestry composition, as the result of migration and admixture, have generated in Italy the largest degree of population structure detected so far in the continent, as well as shaping the amount of Neanderthal DNA in modern-day populations. ; The Leverhulme Trust (F.M. and C.C.); the Italian Ministry of Education, University and Research (MIUR): "Progetti Futuro in Ricerca 2012" (RBFR126B8I) (A.O. and A.A); the "Dipartimenti di Eccellenza (2018–2022)" [Department of Medical Sciences of Turin (G.M.); Department of Biology and Biotechnology of Pavia (A.A., A.O., O.S., and A.T.)]; the Fondazione Cariplo (project 2018-2045; A.T., A.A., and A.O.); the Italian Institute for genomic Medicine (IIGM) and Compagnia di San Paolo Torino, Italy (G.M.); the European Community, Sixth Framework Program (PROCARDIS: LSHM-CT-2007-037273) (S.B.); the Italian Ministry of Health (Besta CEDIR project: RC 2007/LR6, RC 2008/LR6; RC 2009/LR8; RC 2010/LR8; GR-2011-02347041) (G.B.B.); "Progetti di Ricerca finanziati dall'Universita degli Studi di Torino (ex 60%) (2015)" (C.D.G. and G.M.); and ANR-14-CE10-0001 and Region Pays de la Loire (J.G.). G.H. was supported by a grant from the Wellcome Trust/Royal Society 098386/Z/12/Z. S.M. was supported by the Wellcome Trust grant 098387/Z/12/Z and 12284/Z/18/Z. This research was supported by the European Union through the European Regional Development Fund (Projects No. 2014-2020.4.01.16-0030 and 2014.2020.4.01.15) (F.M. and M.M.).