title: Positive selection of lactase persistence among people of Southern Arabia.
abstract: Frequency patterns of the lactase persistence (LP)-associated -13,915 G allele and archaeological records pointing to substantial role played by southern regions in the peopling and domestication processes that involved the Arabian Peninsula suggest that Southern Arabia plausibly represented the center of diffusion of such adaptive variant. Nevertheless, a well-defined scenario for evolution of Arabian LP is still to be elucidated and the burgeoning archaeological picture of complex human migrations occurred through the peninsula is not matched by an equivalent high-resolution description of genetic variation underlying this adaptive trait. To fill this gap, we investigated diversity at a wide genomic interval surrounding the LCT gene in different Southern Arabian populations.
  
  
  
  40 SNPs were genotyped to characterize LCT profiles of 630 Omani and Yemeni individuals to perform population structure, linkage disequilibrium, population differentiation-based and haplotype-based analyses.
  
  
  
  Typical Arabian LP-related variation was found in Dhofaris and Yemenis, being characterized by private haplotypes carrying the -13,915 G allele, unusual differentiation with respect to northern groups and conserved homozygous haplotype-blocks, suggesting that the adaptive allele was likely introduced in the Arabian gene pool in southern populations and was then subjected to prolonged selective pressure.
  
  
  
  By pointing to Yemen as one of the best candidate centers of diffusion of the Arabian-specific adaptive variant, obtained results indicate the spread of indigenous groups as the main process underlying dispersal of LP along the Arabian Peninsula, supporting a refugia model for Arabian demic movements occurred during the Terminal Pleistocene and Early Holocene.
authors.affiliation: Department of Basic Medical Sciences, Mohammed Bin Rashid University, Dubai Healthcare City, Dubai, UAE.
authors.forename: Riad
authors.initials: R
authors.lastname: Bayoumi
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: De Fanti
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Sazzini
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Cristina
authors.identifier: 0000-0002-5318-6502
authors.initials: C
authors.lastname: Giuliani
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Quagliariello
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Bortolini
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Boattini
authors.affiliation: Department of Biochemistry & Molecular Biology, Sana'a University, Sana'a, Yemen.
authors.forename: Molham
authors.initials: M
authors.lastname: Al-Habori
authors.affiliation: Department of Biochemistry & Molecular Biology, Sana'a University, Sana'a, Yemen.
authors.forename: Adel Sharaf
authors.initials: AS
authors.lastname: Al-Zubairi
authors.affiliation: National Geographic and Ronin Institute, Montclair, NJ.
authors.forename: Jeffrey I
authors.initials: JI
authors.lastname: Rose
authors.affiliation: University of Bologna Medical School, Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Romeo
authors.affiliation: Department of Clinical Biochemistry, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman.
authors.forename: Abdulrahim
authors.initials: A
authors.lastname: Al-Abri
authors.affiliation: Laboratory of Molecular Anthropology and Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126, Italy.
authors.forename: Donata
authors.initials: D
authors.lastname: Luiselli
mesh_terms: D000885:Anthropology, Physical; D005828:Genetics, Population; D006239:Haplotypes; D063426:Human Migration; D006801:Humans; D043322:Lactase / Q000235:genetics*; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D044469:Racial Groups / Q000235:genetics; D012641:Selection, Genetic / Q000235:genetics*; D015006:Yemen
chemical_list: D043322:Lactase
keywords: Southern Arabian populations; lactose tolerance; natural selection