Alshamali, F. | bioRxiv Science

bioRxiv2022

Characterization of Arabian Peninsula whole exomes: exploring high inbreeding features

The exome (WES) capture enriched for UTRs on 90 Arabian Peninsula (AP) populations contributed nearly 20,000 new variants from a total over 145,000 total variants. Almost half of these variants were in UTR3, reflecting the low effort we have dedicated to cataloguing these regions, which can bear an important proportion of functional variants, as being discovered in genome-wide association studies. By applying several pathogenic predicting tools, we have demonstrated the high burden in potentially deleterious variants (especially in nonsynonymous and UTR variants located in genes that have been associated mainly with neurologic disease and congenital malformations) contained in AP WES, and the burden was as high as the consanguinity level (inferred as sum of runs of homozygosity, SROH) increased. Arabians had twice SROH values in relation to Europeans and East Asians, and within AP, Saudi Arabia had the highest values and Oman the lowest. We must pursuit cataloguing diversity in populations with high consanguinity, as the potentially pathogenic variants are not eliminated by genetic drift as much as in less consanguineous populations.

genetics↗

bioRxiv2021

Projecting ancient ancestry in modern-day Arabians and Iranians: a key role of the past exposed Arabo-Persian Gulf on human migrations

Arabian Peninsula is strategic for investigations centred on the structuring of the modern human population in the three main groups, in the awake of the out-of-Africa migration. Despite the poor climatic conditions for recovery of ancient DNA human evidence in Arabia, the availability of genomic data from neighbouring ancient specimens and of informative statistical tools allow better modelling the ancestry of these populations. We applied this approach to a dataset of 741,000 variants screened in 291 Arabians and 78 Iranians, and obtained insightful evidence. The west-east axis was a strong forcer of population structure in the Peninsula, and, more importantly, there were clear continuums throughout time linking west Arabia with Levant, and east Arabia with Iran and Caucasus. East Arabians also displayed the highest levels of the basal Eurasian lineage of all tested modern-day populations, a signal that was maintained even after correcting for possible bias due to recent sub-Saharan African input in their genomes. Not surprisingly, east Arabians were also the ones with higher similarity with Iberomaurusians, who were so far the best proxy for the basal Eurasians amongst the known ancient specimens. The basal Eurasian lineage is the signature of ancient non-Africans that diverged from the common European-East Asian pool before 50 thousand years ago, and before the later interbred with Neanderthals. Our results are strong evidence to include the exposed basin of the Arabo-Persian Gulf as possible home of basal Eurasians, to be investigated further on namely by searching ancient Arabian human specimens.

genetics↗