Distribution of MTRR A66G polymorphism among populations from 10 regions in Chinaa.

Abbreviations: MTRR, methionine synthase reductase; AA, “wild-type” homozygosity; AG, heterozygosity; GG, mutant homozygosity; CI, confidence interval.aThe 10 regions include 9 provinces (Shandong, Henan, Shannxi, Jiangsu, Hubei, Yunnan, Guangdong, and Hainan) and 1 municipality (Tianjin).bThe 66G allele frequencies were significantly different among the 10 populations (χ2 = 58.40, PcThe 66GG genotype frequencies were significantly different among the 10 populations (χ2 = 31.23, P = 0.0003).dDeviated significantly from Hardy-Weinberg equilibrium (χ2 = 3.97, P = 0.0464).*The 66G allele and the 66GG genotype frequencies were not significantly different from the southern populations (χ2 = 1.39, P = 0.2381 and χ2 = 1.14, P = 0.2850, respectively).

缩写说明：MTRR，甲硫氨酸合酶还原酶（methionine synthase reductase）；AA：野生型纯合子；AG：杂合子；GG：突变型纯合子；CI：置信区间（confidence interval）。a. 本次纳入的10个研究区域包含9个省份（山东、河南、陕西、江苏、湖北、云南、广东、海南）及1个直辖市（天津）。b. 10个人群间66G等位基因频率存在显著差异（χ²=58.40，Pc）。c. 10个人群间66GG基因型频率存在显著差异（χ²=31.23，P=0.0003）。d. 该位点显著偏离哈迪-温伯格平衡（Hardy-Weinberg equilibrium）（χ²=3.97，P=0.0464）。* 66G等位基因与66GG基因型频率在南方人群中无显著差异（分别为χ²=1.39，P=0.2381；χ²=1.14，P=0.2850）。