Genetic Diversity and Low Stratification of the Population of the United Arab Emirates

Abstract

With high consanguinity rates on the Arabian Peninsula, it would not have been unexpected if the population of the United Arab Emirates (UAE) was shown to be relatively homogenous. However, this study of 1000 UAE nationals provided a contrasting perspective, one of a relatively heterogeneous population. Located at the apex of Europe, Asia, and Africa, the observed diversity could be explained by a plethora of migration patterns since the first Out-of-Africa movement. A strategy to explore the extent of genetic variation of the population of the UAE is presented. The first step involved a comprehensive population stratification study that was instructive for subsequent whole genome sequencing (WGS) of suitable representatives (which is described elsewhere). When these UAE data were compared to previous smaller studies from the region, the findings were consistent with a population that is a diverse and admixed group of people. However, rather than sharp and distinctive clusters, cluster analysis reveals low levels of stratification throughout the population. UAE emirates exhibit high within-Emirate-distance/among-Emirate distance ratios. Supervised admixture analysis showed a continuous gradient of ancestral populations, suggesting that admixture on the south eastern tip of the Arabian Peninsula occurred gradually. When visualized using a unique technique that combined admixture ratios and principal component analysis (PCA), unappreciated diversity was revealed while mitigating projection bias of conventional PCA. We observe low population stratification in the UAE in terms of homozygosity versus separation cluster coefficients. This holds for the UAE in a global context as well as for isolated cluster analysis of the Emirati birthplaces. However, the subtle clustering observed in the Emirates reflects geographic proximity and historic migration events. The analytical strategy used here highlights the complementary nature of data from genotype array and WGS for anthropological studies. Specifically, genotype array data were instructive to select representative subjects for WGS. Furthermore, from the 2.3 million allele frequencies obtained from

Whole Genome Sequencing of Four Representatives From the Admixed Population of the United Arab Emirates

“…For the selection of the four samples, a method combining PCA and supervised admixture analysis described in Tay et al (2020) was used. The admixture ratios were calculated and used to decide on the suitability of each sample to serve as representatives of the different subpopulations of the UAE for WGS.…”

“…The PCA and supervised admixture analysis method described in Tay et al (2020) showed that the UAE population was weakly stratified and followed a gradient continuum admixture of mainly Middle Eastern, Central/South Asian, and Sub-Saharan African components.…”

“…The state of UAE, located at the south eastern corner of the Arabian Peninsula stretches along the coastline of the Arabian Gulf on the north, is surrounded by Oman, Saudi Arabia, Qatar, and Iran. Although its pivotal geographic position and diverse population makes it important to study in order to understand the patterns of migration in the region, the ancestry of its contemporary population remains obscure as there has been no in-depth genetic study presented to date except for two recent publications (Fernandes et al, 2019;Tay et al, 2020).…”

“…In addition to the detailed early migration movements in the Arabian Peninsula described in Tay et al (2020), the area has experienced relatively recent waves of population traffic. The territory bounded by the borders of the UAE has undergone a seasonal influx of Arab tribes from Yemen as well as Central and Northern Arabia (Bey, 1996).…”

“…These subjects represent the different subpopulations that exist within and constitute the historical ethnic admixture that is found within the current UAE population. The selection of the four suitable subpopulation representatives has been informed by a preceding comprehensive population structure analysis (Tay et al, 2020) based on their subpopulation centrality and admixture. The novel strategies described in the paper have been used to gain a comprehensive overview of the UAE's genetic landscape.…”