Low Level Radiation Research Section (LLRRS), Radiation Biology and Health Sciences Division (RB&HSD), Bhabha Atomic Research Centre, Mumbai, India.
Low Level Radiation Research Laboratory (LLRRL), LLRRS, RB&HSD, Bio-Science Group, Bhabha Atomic Research Centre, Mumbai, India.
Int J Radiat Biol. 2020 Jun;96(6):734-739. doi: 10.1080/09553002.2020.1739771. Epub 2020 Mar 19.
Single Nucleotide Polymorphisms (SNPs) at DNA repair genes are considered as potential biomarkers of radio-sensitivity. The coastal belt of Kerala in south west India has a patchy distribution of monazite in its beach sand that contains Th-232 and its decay products. Thus, radiation levels in this area vary from <1.0mGy to 45.0mGy/year. The areas with external gamma radiation dose >1.5mGy/year are considered as High-Level Natural Radiation Areas (HLNRA) and ≤ 1.5mGy/year are Normal Level Natural Radiation Area (NLNRA). In the present study, an attempt was made to evaluate the influence of chronic low dose radiation exposure on DNA repair gene polymorphisms in NLNRA and HLNRA population of Kerala coast. Genomic DNA was isolated from venous blood samples of 246 random, healthy individuals (NLNRA, = 104; HLNRA, = 142) and genotyping of five SNPs such as X-ray repair cross complementing 1(), X-ray repair cross complementing 3 (], Protein kinase, DNA-activated, catalytic subunit () (X-ray repair cross-complementing group 7, ), nei like DNA glycosylase 1 () and DNA ligase 1 () was carried out using PCR based restriction fragment length polymorphism (PCR-RFLP) followed by silver staining. Our results showed no significant difference in genotype frequencies in HLNRA vs NLNRA at three of the five SNPs studied i.e. (χ = 5.85, = .054), (χ = 0.71, = .339), ( G/T) (χ = 3.72, = .156), whereas significant difference was observed at (χ =8.71, = .013) and A/C (χ = 7.66, = .022). The odds of heterozygote to homozygote genotypes in HLNRA relative to NLNRA at Arg399Gln (OR = 1.96, 95% CI: 1.13-3.40), Thr241Met (OR = 0.73, 95% CI: 0.41-1.31), (OR = 0.81; 95% CI: 0.48-1.38), (OR = 0.54; 95% CI: 0.31-0.96) and (OR = 1.62; 95% CI: 0.97-2.69) was also not significantly different in HLNRA vs NLNRA, except at and The genotype frequencies at three of these SNPs i.e. and () were similar, whereas and showed significant difference between HLNRA and NLNRA population. However, further research using more number of SNPs in a larger cohort is required in this study area.
单核苷酸多态性（SNPs）在 DNA 修复基因中被认为是放射敏感性的潜在生物标志物。印度西南部喀拉拉邦的沿海地区，其海滩砂中分布着钍-232 及其衰变产物独居石。因此，该地区的辐射水平从<1.0mGy 到 45.0mGy/年不等。外部γ辐射剂量大于 1.5mGy/年的区域被认为是高水平自然辐射区（HLNRA），而≤1.5mGy/年的区域是正常水平自然辐射区（NLNRA）。在本研究中，我们试图评估慢性低剂量辐射暴露对喀拉拉邦海岸 NLNRA 和 HLNRA 人群中 DNA 修复基因多态性的影响。从 246 名随机健康个体的静脉血样中提取基因组 DNA（NLNRA，=104；HLNRA，=142），并使用基于聚合酶链反应的限制性片段长度多态性（PCR-RFLP）进行五个 SNPs（如 X 射线修复交叉互补 1()、X 射线修复交叉互补 3()、蛋白激酶，DNA 激活，催化亚基()（X 射线修复交叉互补组 7，）、neilike DNA 糖基化酶 1()和 DNA 连接酶 1()）的基因分型，随后进行银染。我们的研究结果显示，在研究的五个 SNPs 中，有三个 SNPs（即，（χ=5.85，=0.054）、（χ=0.71，=0.339）和（G/T）（χ=3.72，=0.156）），HLNRA 与 NLNRA 之间的基因型频率没有显著差异，而在和 A/C（χ=7.66，=0.022）中则存在显著差异。与 NLNRA 相比，HLNRA 中杂合子到纯合子基因型的比值在 Arg399Gln（OR=1.96，95%CI：1.13-3.40）、Thr241Met（OR=0.73，95%CI：0.41-1.31）、（OR=0.81；95%CI：0.48-1.38）、（OR=0.54；95%CI：0.31-0.96）和（OR=1.62；95%CI：0.97-2.69）中也没有显著差异，除了和。这些 SNPs 中的三个（即和（））的基因型频率相似，而和则显示 HLNRA 和 NLNRA 之间存在显著差异。然而，在这个研究区域，需要使用更多的 SNP 并在更大的队列中进行进一步的研究。
