title: A gradient of NOS1 overproduction alleles in European and Mediterranean populations.
abstract: OBJECTIVE
  A (CA)n repeat located in the 3' UTR region of exon 29 of the NOS1 gene (encoding for neuronal nitric oxide synthase) has been shown to affect the size of mRNA. NOS1 mRNA is highly diverse, contributing to changes in transcript generation, degradation, processing, or subcellular targeting. In the present work, we analyzed allele frequencies of this (CA)n repeat in nine populations of the Mediterranean area and Middle Europe. We aimed at testing the presence of a north-south positive gradient of frequencies of ≤17 allele repeats, compatible with the hypothesis of positive selection suggested in two of our previous works, related to the past prevalence of malaria infection in Europe.
  
  
  RESULTS
  Results show significant negative correlations of latitude with frequencies of alleles S and genotypes S/S and S/L (p < 0.01).
  
  
  CONCLUSIONS
  In conclusion, the north-south gradient of S alleles found in the present work would confirm our previous observation about the NOS1 gene, reinforcing the hypothesis of a selective action of malaria infection. This hypothesis is strengthened by the role of nitric oxide in the immunity system.
authors.affiliation: Faculty of Science, University of Corsica, Corsica, France. is.piras@tiscali.it
authors.forename: Ignazio
authors.initials: I
authors.lastname: Piras
authors.forename: Alessandra
authors.initials: A
authors.lastname: Falchi
authors.forename: Pedro
authors.initials: P
authors.lastname: Moral
authors.forename: Giorgio
authors.initials: G
authors.lastname: Paoli
authors.forename: Carla Maria
authors.initials: CM
authors.lastname: Calò
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vona
authors.forename: Laurent
authors.initials: L
authors.lastname: Varesi
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics*; D000483:Alleles; D018900:Dinucleotide Repeats / Q000235:genetics*; D004790:Enzyme Induction / Q000235:genetics; D005060:Europe / Q000453:epidemiology; D005091:Exons / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008288:Malaria / Q000453:epidemiology / Q000235:genetics / Q000276:immunology; D008297:Male; D019083:Mediterranean Region / Q000453:epidemiology; D052248:Nitric Oxide Synthase Type I / Q000235:genetics* / Q000502:physiology; D058974:Phylogeography; D012641:Selection, Genetic
chemical_list: D020413:3' Untranslated Regions; C496320:NOS1 protein, human; D052248:Nitric Oxide Synthase Type I