Association Between Mitochondrial DNA Polymorphism And Altitude Environmental Adaptability In Tibetan Population

Objective:Mitochondria are the only organelles containing DNA outside the nucleus of the human body.The functional realization of mtDNA is not only related to its structural integrity but also to its copy number.The increase in the copy number of mtDNA is considered to be the compensation of the mitochondrial respiratory function.mtDNA has genetic material that is independent of nuclear genes and is strictly maternally inherited.It has high copy,high mutation rate,large intra-population variation,lack of recombination,poor degradation,lack of histone protection,and lack of relevant repair mechanisms.mtDNA has high polymorphism in different ethnic groups,different regions and different altitudes.Studies have shown that some haplotype genes of mtDNA are significantly higher in the case of high altitude pulmonary edema than in the control group.During the adaptation of the plateau environment,the morphology and function of mitochondria and the sequence of mtDNA will change.This study investigated the mtDNA hypervariable regions of the Naqu Tibetan population and explored the effects of mtDNA on the adaptability of the plateau environment.Research: In this study,blood samples of 207 volunteers from Naqu Tibetan population were used for research.DNA was extracted from blood samples by phenol-chloroform method,and dissolved in TE solution at 4? for storage.The target DNA was amplified by PCR using template technology.After amplification,agarose gel electrophoresis was used to detect whether the target fragment was successfully amplified.The amplified samples were sent to Taihe Biotechnology Co.,(Beijing).for sequencing.After the sequences were compared,the haplogroups of the sequences were analyzed,the PIC value was calculated,and the genetic distance from other ethnic samples was analyzed.Results: 1.The haploid data of mt DNA obtained in this experiment has a polymorphic information content(PIC)of 0.995146,and the data polymorphism is good.2.In this experiment,the mitochondrial DNA haplogroups of the Naqu Tibetans in China were compared with mitochondrial DNA samples from several ethnic groups and other countries.It was found that the Naqu Tibetan and Yanbian Korean branches are the closest,and the Pakistan branch is the farthest.3.Principal component analysis of mitochondrial DNA data of other nationalities and other countries in the country,the twoprincipal components accounted for 37.431% and 22.937% of the total variance,respectively.In addition to being closer to the Yanbian Koreans and East Timorese populations,the Naqu Tibetans have not been far away from their genetic distance from the Naqu Tibetan population.The genetics of the Pakistani population,other races and other countries have any close ties.The genetic distance of the population of South Korea is relatively close to that of Northern Han,Guangdong Han,Henan Han,Gelao.The furthest distance.Conclusions: 1.The mt DNA haplogroup of the Naqu Tibetans has a good frequency distribution and can be applied to the study of altitude sickness.2.The haplogroup M9 is of great research value in the direction of altitude sickness.3.Genetic differentiation index,phylogenetic tree and principal component analysis of the Naqu Tibetan population and the Yanbian Korean population are closer in genetic distance.research value.