david brooks articles about the middle east

The toggling from humid to arid periods in the late Pleistocene and Holocene has been proposed to result in population movements adapting to the climate. Although most of Arabia is a hyper-arid desert today, there were several humid periods resulting in a “green Arabia” in the past which facilitated human dispersals, with the onset of the current desert climate thought to have started around 6 kya ( Petraglia et al., 2020). In addition, tools and footprints attributed to modern humans have also been identified in Arabia ∼120 kya ( Armitage et al., 2011 Stewart et al., 2020). The region contains some of the earliest evidence of modern humans outside Africa, with fossils dated to at least 177 thousand years ago (kya) and ∼85 kya identified in the Levant and North West Arabia, respectively ( Hershkovitz et al., 2018 Groucutt et al., 2018). Situated between Africa, Europe, and South Asia, it forms an important region to understand human evolution, history, and migrations. A region particularly understudied by large-scale sequencing projects is the Middle East ( Fernandes et al., 2019 Abou Tayoun and Rehm, 2020). However, many populations remain understudied, which restricts our understanding of genetic variation and population history and may exacerbate health inequalities ( Sirugo et al., 2019). Global whole-genome sequencing projects have provided insights into human diversity, dispersals, and past admixture events ( Bergström et al., 2020 Mallick et al., 2016 GenomeAsia100K Consortium, 2019 1000 Genomes Project Consortium et al., 2015). Our results provide detailed insights into the genomic and selective histories of the Middle East. Finally, we identify variants that show evidence of selection, including polygenic selection. We found an association between movement and admixture of populations in the region and the spread of Semitic languages. Arabians suffered a population bottleneck around the aridification of Arabia 6 kya, while Levantines had a distinct bottleneck overlapping the 4.2 kya aridification event. Population sizes within the region started diverging 15–20 kya, when Levantines expanded while Arabians maintained smaller populations that derived ancestry from local hunter-gatherers. We found no genetic traces of early expansions out-of-Africa in present-day populations but found Arabians have elevated Basal Eurasian ancestry that dilutes their Neanderthal ancestry. Here, we generated 137 high-coverage physically phased genome sequences from eight Middle Eastern populations using linked-read sequencing. The Middle East region is important to understand human evolution and migrations but is underrepresented in genomic studies.

David brooks articles about the middle east