携带EGLN1不同SNPs基因型对汉族人群适应青藏高原低氧环境的作用研究

Effects of different SNPs genotypes of EGLN1 gene on the adaptation to the hypoxic environment of Qinghai-Tibet Plateau in Han population

目的了解脯氨酸羟化酶2(EGLN1)基因突变位点在世居青藏高原内外的藏族和汉族中的差异及其与后者进入青藏高原后血液指标改变的相关性。方法随机挑选健康志愿者100名,BMI正常,无吸烟史,其中世居青藏高原藏族50名,男女各25名,年龄18—55(33.9±8.3)岁,四川成都汉族50名,男性26名,女性24名,年龄13—45(33.6±9.2)岁。应用血液基因组DNA提取试剂盒参照试剂盒操作说明书提取100μL/人(份)DNA,共100份,应用聚合酶链式反应(PCR)结合测序技术进行EGLN1基因2个单核苷酸多态位点(SNPs)rs12097901, rs2790859检测。再随机挑选50名四川成都汉族男性健康志愿者作为高原低氧习服组,年龄19—23(20.9±1.0)岁,提取100μl/人(份)DNA,共50份,检测其进入高原前后的血常规,选择青藏高原前后Hb差值≥35 g/L、红细胞计数(RBC)差值≥1×1012/L和红细胞比容(Hct)差值≥0.1的20名作为低氧习服观察组,其余凡小于3项指标差值中任1项者共30名作为低氧习服对照组,分析汉族人群中携带不同SNPs基因型者的血红蛋白浓度(Hb)差异,并比较2组人群携带EGLN1基因单体型的差异。结果本组世居青藏高原内外的藏族和汉族人群比较,EGLN1基因rs12097901位点G、rs2790859位点C等位基因频率分别为85.0%(85/100)vs 46.0%(46/100)、20.0%(10/100)vs 49.0%(49/100)(P<0.01);单体型分析:C-C、G-T比例分别为11.74%(11.74/100)vs 46.81%(46.81/100)、76.74%(76.74/100)vs 41.81%(41.81/100)(P<0.01)。进入青藏高原前后汉族人群低氧习服观察组与低氧习服对照组EGLN1基因G-C单体型比例为0(0/40)vs 9.60%(5.75/60)(P<0.05)。结论 EGLN1基因rs12097901(C>G)和rs2790859(T>C)位点突变与世居青藏高原藏族适应高原低氧环境存在紧密相关性。汉族人进入高原后,携带EGLN1基因rs12097901和rs2790859位点G-C单体型,可避免自身红细胞过度增生导致高原红细胞增多症,利于青藏高原低氧习服。

Objective To explore the difference in EGLN1 genetic variation between the Tibetans who are conditioned to live at Qinghai-Tibet Plateau(>3500 m)and Han population conditioned to 500 m above sea level,and to analyze the correlation between the hematological indicators and hypoxic adaptation for people living at plain areas(500 m)upon entering hypoxic environment with high altitudes(>3 500 m).Methods The blood samples were collected from 100 healthy volunteers.50 of them were Tibetans in high altitude(3 700 m),including 25 males and 25 females,aged 18—55(33.9±8.3)years.The other 50 of them were Han people in Chengdu at 500 m above sea level,including 26 males and 24 females,aged 13—45(33.6±9.2)years.All volunteers had normal BMI and no history of smoking.Genomic DNA was extracted from these blood samples.DNA with 100μL each sample were extracted by using blood genomic DNA extraction kit in a total of 100 blood samples according to the manufacturer′s instructions.The single nucleotide polymorphisms(SNPs)rs12097901 and rs2790859 of EGLN1 gene were screening by polymerase chain reaction(PCR)combined with sequencing.50 healthy male volunteers of Han population in Chengdu were randomly selected as high altitude hypoxia acclimatization group,aged 19—23(20.9±1.0)years.50 samples DNA were extracted based on the above method,and blood samples routine were conducted before and after entering the plateau.Threshold values were drawn in Hb≥35 g/L,RBC count at≥1×1012/L and Hct at≥0.1 for the 50 Han population entering higher altitudes,20 cases who met the above three indexes were taken as the observation group of hypoxia acclimatization at high altitude,and 30 cases with one dissatisfaction as the control group of hypoxia acclimatization at high altitude.Hematological changes in samples with different haplotypes were then analyzed.Results The G allele frequency of EGLN1 gene rs12097901 in Tibetans and Han was 85.0%(85/100)vs.46.0%(46/100)(P<0.01),and the C allele frequency of rs2790859 was 20.0%(10/100)vs.49.0%(49/100)(P<0.01).Haplotype analysis:the ratio of C-C and G-T in Tibetans and Han was 11.74%(11.74/100)vs.46.81%(46.8/100)and 76.74%(76.74/100)vs.41.81%(41.8/100)(P<0.01),respectively.Before and after entering the Qinghai-Tibet Plateau,the proportion of EGLN1 gene G-C haplotype in the hypoxia acclimatization observation group and the hypoxia acclimatization control group was 0(0/40)vs.9.60%(5.75/60)(P<0.05).Conclusion The variation of EGLN1 gene rs12097901(C>G)and rs2790859(T>C)are associated with hypoxic adaptation in Qinghai-Tibet Plateau in Tibetans.After entering the plateau,the Han population carrying EGLN1 gene rs12097901 and rs2790859 site G-C haplotype can avoid high altitude polycythemia caused by self-erythrocytosis,which is beneficial for Han popuLation to hypoxia acclimatization in Qinghai-Tibet Plateau.