Xu Lidan, Sun Haiming, Zhang Xuelong, Wang Jingwei, Sun Donglin, Chen Feng, Bai Jing, Fu Songbin
Laboratory of Medical Genetics, Harbin Medical University, Harbin, China.
Scand J Gastroenterol. 2010;45(2):168-74. doi: 10.3109/00365520903414176.
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.
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.
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.
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.
据报道，乳糖酶基因内的一些单核苷酸多态性（-13910C/T、-22018G/A、-13907C/G、-13915T/G和-14010G/C）与乳糖酶持续性相关。在我们之前的研究中，我们发现-13910C/T在中国人群中并非乳糖酶持续性的良好预测指标。为了更好地理解乳糖酶持续性的机制，我们检测了中国北方其他四个与乳糖酶持续性相关等位基因的频率。
我们采用聚合酶链反应-限制性片段长度多态性和重测序方法，评估了六个中国北方人群（满族、蒙古族、赫哲族、鄂伦春族、哈萨克族和北方汉族）中-22018G/A、-13907C/G、-13915T/G和-14010G/C的等位基因频率。
通过对1092条染色体进行基因分型，我们发现-22018A等位基因频率在哈萨克族人群中最高，在北方汉族人群中极低。尽管关于中国北方人群乳糖酶持续性频率的可用数据很少，但我们将等位基因频率与先前发表的表型频率进行了比较。我们发现-22018A等位基因频率与中国北方报道的乳糖酶持续性频率基本一致。关于-13907C/G、-13915T/G和-14010G/C多态性，我们未发现携带衍生等位基因的个体。
-22018A等位基因频率在这六个群体中差异显著，且该频率反映了乳糖酶持续性频率。考虑到先前研究的结果，我们认为不同游牧群体中与乳糖酶持续性相关等位基因的起源不同。
