title: The -22018A allele matches the lactase persistence phenotype in northern Chinese populations.
abstract: OBJECTIVE
  It has been reported that some single-nucleotide polymorphisms (-13910C/T, -22018G/A, -13907C/G, -13915T/G, and -14010G/C) within the lactase gene are associated with lactase persistence. In our previous study, we found that -13910C/T is not a good predictor of lactase persistence in Chinese populations. To obtain a better understanding of the mechanism of lactase persistence, we examined the frequencies in Northern China of the four other alleles that are associated with lactase persistence.
  
  
  METHODS
  We evaluated the allele frequencies of -22018G/A, -13907C/G, -13915T/G, and -14010G/C in six northern Chinese populations (Manchu, Mongol, Hezhen, Oroqen, Kazak, and northern Han) using the methods of polymerase chain reaction-restriction fragment length polymorphism and resequencing.
  
  
  RESULTS
  By genotyping 1092 chromosomes, we found that the frequency of the -22018A allele was highest in the Kazak population and extremely low in the northern Han population. Although there are little available data about the frequency of lactase persistence in northern Chinese populations, we compared the allele frequencies with the phenotype frequencies that have been published previously. We found that the frequency of the -22018A allele was basically consistent with the reported frequencies of lactase persistence in Northern China. With respect to the -13907C/G, -13915T/G, and -14010G/C polymorphisms, we found no individuals with the derived allele.
  
  
  CONCLUSIONS
  The frequency of the -22018A allele differed significantly among the six populations and the frequency reflected the frequency of lactase persistence. Taking into consideration the results of previous studies, we believe that the origins of lactase persistence-associated alleles are different in different pastoral populations.
authors: Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
authors: Lidan
authors: L
authors: Xu
authors: Haiming
authors: H
authors: Sun
authors: Xuelong
authors: X
authors: Zhang
authors: Jingwei
authors: J
authors: Wang
authors: Donglin
authors: D
authors: Sun
authors: Feng
authors: F
authors: Chen
authors: Jing
authors: J
authors: Bai
authors: Songbin
authors: S
authors: Fu
mesh_terms: D000483:Alleles; D044466:Asian People / Q000235:genetics; D002681:China; D005787:Gene Frequency; D005828:Genetics, Population; D005838:Genotype; D006801:Humans; D043322:Lactase / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide
chemical_list: D043322:Lactase