title: Distributions of the GSTM1 and GSTT1 null genotypes worldwide are characterized by latitudinal clines.
abstract: BACKGROUND
  Deletion types of genetic variants of glutathione S-transferase (GST) M1 and T1, the GSTM1 null and GSTT1 null which are risk factors for certain cancers, have been ubiquitously found in human populations but their worldwide distribution pattern is unclear.
  
  
  METHODS
  To perform a meta-analysis, a systematic search for the literature on GSTM1 and GSTT1 null genotypes was done to identify 63 reports for 81 human populations. Relationships between the GSTM1 and GSTT1 null genotype frequencies and the absolute latitude of 81 populations were tested by Spearman's rank correlation coefficient.
  
  
  RESULTS
  A significant positive correlation was detected between the GSTM1 null genotype frequency and the absolute latitude (r=0.28, p-value <0.05), whereas the GSTT1 null genotype frequency and absolute latitude showed a significant negative correlation (r= -0.41 p-value <0.01). There was no correlation between the frequencies of GSTM1 and GSTT1 null genotype in each population (r= -0.029, p-value=0.80).
  
  
  CONCLUSIONS
  Latitudinal clines of the distribution of the GSTM1 and GSTT1 null genotypes may be attributed to the result of gene-environmental adaptation. No functional compensation between GSTM1 and GSTT1 was suggested by the lack of correlation between the null frequencies for GSTM1 and GSTT1.
authors: Unit of Human Biology and Genetics, Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan E-mail : tishida@bs.s.u-tokyo.ac.jp.
authors: Marie
authors: M
authors: Saitou
authors: Takafumi
authors: T
authors: Ishida
mesh_terms: D017353:Gene Deletion; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D009369:Neoplasms / Q000235:genetics*
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1