title: Distribution of cytokine gene single nucleotide polymorphisms among a multi-ethnic Iranian population.
abstract: BACKGROUND
  Cytokine gene single nucleotide polymorphisms (SNPs) are widely used to study susceptibility to complex diseases and as a tool for anthropological studies.
  
  
  METHODS
  To investigate cytokine SNPs in an Iranian multi-ethnic population, we have investigated 10 interleukin (IL) SNPs (IL-1β (C-511T, T-31C), IL-2 (G-384T), IL-4 (C-590T), IL-6 (G-174C), IL-8 (T-251A), IL-10 (G-1082A, C-819T, C-592A) and tumor necrosis factor-alpha (TNF-α) (G-308A) in 415 Iranian subjects comprising of 6 different ethnicities. Allelic and genotypic frequencies as well as Hardy-Weinberg equilibrium (HWE) were calculated by PyPop software. Population genetic indices including observed heterozygosity (Ho), expected heterozygosity (He), fixation index (FIS), the effective number of alleles (N e) and polymorphism information content (PIC) were derived using Popgene 32 software. Multidimensional scaling (MDS) was constructed using Reynold's genetic distance obtained from the frequencies of cytokine gene polymorphism.
  
  
  RESULTS
  Genotypic distributions were consistent with the HWE assumptions, except for 3 loci (IL-4-590, IL-8-251 and IL-10-819) in Fars and 4 loci (IL-4-590, IL-6-174, IL-10-1082 and TNF-α-308) in Turks. Pairwise assessment of allelic frequencies, detected differences at the IL-4-590 locus in Gilakis versus Kurds (P = 0.028) and Lurs (P = 0.022). Mazanis and Gilakis displayed the highest (Ho= 0.50 ± 0.24) and lowest (Ho= 0.34 ± 0.16) mean observed heterozygosity, respectively.
  
  
  CONCLUSIONS
  MDS analysis of our study population, in comparison with others, revealed that Iranian ethnicities except Kurds and Mazanis were tightly located within a single cluster with closest genetic affinity to Europeans.
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran ; Department of Molecular Genetics, Fars Science and Research Branch, Islamic Azad University, Shiraz, Iran.
authors.forename: Zana Karimi
authors.initials: ZK
authors.lastname: Kurdistani
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Samaneh
authors.initials: S
authors.lastname: Saberi
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Yeganeh
authors.initials: Y
authors.lastname: Talebkhan
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Oghalaie
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Esmaeili
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Mohajerani
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Bababeik
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Parisa
authors.initials: P
authors.lastname: Hassanpour
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Shaghik
authors.initials: S
authors.lastname: Barani
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Farjaddoost
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Ebrahimzadeh
authors.affiliation: Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Jean
authors.initials: J
authors.lastname: Trejaut
authors.affiliation: HPGC Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran.
authors.forename: Marjan
authors.initials: M
authors.lastname: Mohammadi
keywords: Allelic frequency; Arlequin; genetic diversity; polymorphism information content; single nucleotide polymorphisms