TY - JOUR
T1 - The influence of admixture and consanguinity on population genetic diversity in Middle East
AU - Yang, Xiong
AU - Al-Bustan, Suzanne
AU - Feng, Qidi
AU - Guo, Wei
AU - Ma, Zhiming
AU - Marafie, Makia
AU - Jacob, Sindhu
AU - Al-Mulla, Fahd
AU - Xu, Shuhua
PY - 2014/11/11
Y1 - 2014/11/11
N2 - The Middle East (ME) is an important crossroad where modern humans migrated 'out of Africa' and spread into Europe and Asia. After the initial peopling and long-term isolation leading to well-differentiated populations, the ME also had a crucial role in subsequent human migrations among Africa, Europe and Asia; thus, recent population admixture has been common in the ME. On the other hand, consanguinity, a well-known practice in the ME, often reduces genetic diversity and works in opposition to admixture. Here, we explored the degree to which admixture and consanguinity jointly affected genetic diversity in ME populations. Genome-wide single-nucleotide polymorphism data were generated in two representative ME populations (Arabian and Iranian), with comparisons made with populations worldwide. Our results revealed an overall higher genetic diversity in both ME populations relative to other non-African populations. We identified a much larger number of long runs of homozygosity in ME populations than in any other populations, which was most likely attributed to high levels of consanguineous marriages that significantly decreased both individual and population heterozygosity. Additionally, we were able to distinguish African, European and Asian ancestries in ME populations and quantify the impact of admixture and consanguinity with statistical approaches. Interestingly, genomic regions with significantly excessive ancestry from individual source populations are functionally enriched in olfactory pathways, which were suspected to be under natural selection. Our findings suggest that genetic admixture, consanguinity and natural selection have collectively shaped the genetic diversity of ME populations, which has important implications in both evolutionary studies and medical practices.
AB - The Middle East (ME) is an important crossroad where modern humans migrated 'out of Africa' and spread into Europe and Asia. After the initial peopling and long-term isolation leading to well-differentiated populations, the ME also had a crucial role in subsequent human migrations among Africa, Europe and Asia; thus, recent population admixture has been common in the ME. On the other hand, consanguinity, a well-known practice in the ME, often reduces genetic diversity and works in opposition to admixture. Here, we explored the degree to which admixture and consanguinity jointly affected genetic diversity in ME populations. Genome-wide single-nucleotide polymorphism data were generated in two representative ME populations (Arabian and Iranian), with comparisons made with populations worldwide. Our results revealed an overall higher genetic diversity in both ME populations relative to other non-African populations. We identified a much larger number of long runs of homozygosity in ME populations than in any other populations, which was most likely attributed to high levels of consanguineous marriages that significantly decreased both individual and population heterozygosity. Additionally, we were able to distinguish African, European and Asian ancestries in ME populations and quantify the impact of admixture and consanguinity with statistical approaches. Interestingly, genomic regions with significantly excessive ancestry from individual source populations are functionally enriched in olfactory pathways, which were suspected to be under natural selection. Our findings suggest that genetic admixture, consanguinity and natural selection have collectively shaped the genetic diversity of ME populations, which has important implications in both evolutionary studies and medical practices.
UR - http://www.scopus.com/inward/record.url?scp=84925849533&partnerID=8YFLogxK
U2 - 10.1038/jhg.2014.81
DO - 10.1038/jhg.2014.81
M3 - Article
C2 - 25253659
AN - SCOPUS:84925849533
VL - 59
SP - 615
EP - 622
JO - Journal of Human Genetics
JF - Journal of Human Genetics
SN - 1434-5161
IS - 11
ER -