title: Saudi Arabian Y-Chromosome diversity and its relationship with nearby regions.
abstract: BACKGROUND
  Human origins and migration models proposing the Horn of Africa as a prehistoric exit route to Asia have stimulated molecular genetic studies in the region using uniparental loci. However, from a Y-chromosome perspective, Saudi Arabia, the largest country of the region, has not yet been surveyed. To address this gap, a sample of 157 Saudi males was analyzed at high resolution using 67 Y-chromosome binary markers. In addition, haplotypic diversity for its most prominent J1-M267 lineage was estimated using a set of 17 Y-specific STR loci.
  
  
  RESULTS
  Saudi Arabia differentiates from other Arabian Peninsula countries by a higher presence of J2-M172 lineages. It is significantly different from Yemen mainly due to a comparative reduction of sub-Saharan Africa E1-M123 and Levantine J1-M267 male lineages. Around 14% of the Saudi Arabia Y-chromosome pool is typical of African biogeographic ancestry, 17% arrived to the area from the East across Iran, while the remainder 69% could be considered of direct or indirect Levantine ascription. Interestingly, basal E-M96* (n = 2) and J-M304* (n = 3) lineages have been detected, for the first time, in the Arabian Peninsula. Coalescence time for the most prominent J1-M267 haplogroup in Saudi Arabia (11.6 +/- 1.9 ky) is similar to that obtained previously for Yemen (11.3 +/- 2) but significantly older that those estimated for Qatar (7.3 +/- 1.8) and UAE (6.8 +/- 1.5).
  
  
  CONCLUSIONS
  The Y-chromosome genetic structure of the Arabian Peninsula seems to be mainly modulated by geography. The data confirm that this area has mainly been a recipient of gene flow from its African and Asian surrounding areas, probably mainly since the last Glacial maximum onwards. Although rare deep rooting lineages for Y-chromosome haplogroups E and J have been detected, the presence of more basal clades supportive of the southern exit route of modern humans to Eurasian, were not found.
authors.affiliation: Molecular Genetics Laboratory, College of Medicine, King Saud University, Riyadh 11411, Saudi Arabia. abuamero@gmail.com
authors.forename: Khaled K
authors.initials: KK
authors.lastname: Abu-Amero
authors.forename: Ali
authors.initials: A
authors.lastname: Hellani
authors.forename: Ana M
authors.initials: AM
authors.lastname: González
authors.forename: Jose M
authors.initials: JM
authors.lastname: Larruga
authors.forename: Vicente M
authors.initials: VM
authors.lastname: Cabrera
authors.forename: Peter A
authors.initials: PA
authors.lastname: Underhill
mesh_terms: D044383:Black People / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D004641:Emigration and Immigration; D019143:Evolution, Molecular; D051456:Gene Flow; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D012529:Saudi Arabia; D017422:Sequence Analysis, DNA