| Purpose: Current research shows that the incidence and mortality of prostate cancer vary among different races,and that one of the main mechanisms leading to this discrepancy is the markedly different methylation levels of prostate cancer genomes in different races.In this experiment,by analyzing the differences in genomic methylation between Mongolian and Han prostate cancer patients in Inner Mongolia,the characteristics of genomic methylation in prostate cancer between Mongolian and Han people were discussed.Methods: High-throughput sequencing was used in 5 patients with prostate cancer(3in Mongolian and 2 in Han).And 2 cases of Mongolian healthy normal people.Three Mongolian prostate cancer patients were set as the experimental group(T1,T2,T3respectively);two Han prostate cancer patients were divided into the control group B or Control B group(C1,C2);2 Healthy people in Mongolia group were control group A,namely Control A group(C3,C4).Blood samples were taken from each group of people,and DNA was extracted.Based on the Illumina hiseq XTen sequencing platform,combined with genome-wide Bisulfite processing and biological information data analysis,genomic methylation of Mongolian population(prostate cancer,normal people)and Han prostate cancer population Model,by further comparing the degree of genomic methylation between Mongolian prostate cancer and Han prostate cancer,Mongolian prostate cancer,and Mongolian normal people,the genomic regions with significant differences in methylation levels(Differentially Methylated Region,DMR)annotate the gene structure and clarify the methylation of each gene structure,so as to obtain differential methylation results of the genome.Result:1.By comparing 3 Mongolian prostate cancer samples with 2 Han prostate cancer samples,the following research results were obtained:(1)The overall C methylation level of Mongolian prostate cancer genome ranges from 2.52% to 2.65%;CG methylation level ranges from 74.51% to 77.94%.The overall C methylation level of the Han prostate cancer genome ranges from 3.54% to3.57%.CG methylation levels ranged from 83.97% to 84.33%.The overall C and CG methylation levels of the Mongolian prostate cancer genome are lower than that of the Han prostate cancer;and the sample genomes of the Mongolian prostate cancer and Han prostate cancer are in all methylated cytosines.The proportion of pyrimidine accounts for> 99% of all methylated cytosines,while the proportion of methylated cytosines of CHG and CHH types is very small.(2)Mongolian prostate cancer and Han prostate cancer in all genomic regions(Intergenic,Exon,Gene,UTR3,Intron,UTR5,Promoter)CG methylation levels are significantly higher than C,CHG,CHH methylation levels;and Compared with Han prostate cancer,the level of C methylation in all genomic regions of Mongolian prostate cancer was lower than that of Han prostate cancer,which was statistically different(P?0.05).The CG,CHG,and CHH methylation levels in all genomic regions of Mongolian prostate cancer were not statistically different from that of Han prostate cancer(P> 0.05).(3)Analyze the proportions of C sites(CG,CHG,and CHH)of Mongolian prostate cancer and Han prostate cancer samples in different methylation environments to all methylation C sites.The results show that compared with CHG and CHH The methylation of CG in Mongolian prostate cancer and Han prostate cancer genome is at a high methylation level.(4)We use Motif to analyze the genomes of Mongolian prostate cancer and Han prostate cancer in different methylation environment(high methylation level,middle methylation level,low methylation level)and methylation C sites.(CG,CHG,and CHH)Is there a preference for base sequences in the 9bp range? The analysis results show that the genomes of Mongolian prostate cancer and Han prostate cancer are different in the methylation environment in the methylation C site of each type in the9 bp range of the preferred base sequences are different.It is worth noting that,in the genomes of the above two populations,the H preference of CHG is adenine,the first H preference of CHH is adenine,and the second preference is thymine.(5)We analyzed genomic regions(DMRs)with significantly different methylation levels between the Mongolian prostate cancer and Han prostate cancer genomes.The study found that Mongolian prostate cancer and Han prostate cancer detected 5246 DMRs in all genomes.Analysis of the methylation levels of all DMRs of Mongolian prostate cancer and Han prostate cancer,found that compared with Han prostate cancer,the average methylation level of Mongolian prostate cancer DMR is lower than that of Han prostate cancer,the difference is statistically significant(P?0.05).Annotating the genetic structure of all DMRs,we found that Mongolian prostate cancer and Han prostate cancer had the highest number of DMRs annotated to Intron in all genomes,followed by Promoter,and the least number of DMRs annotated to UTR3 and UTR5.Statistics on the distribution of DMR in the genomic structures of Mongolian prostate cancer and Han prostate cancer.It was found that the number of CGI hypermethylated DMRs was higher than the number of low methylated DMRs in the genomes of the two populations,and the difference was statistically significant(P?0.05).).The number of hypermethylated DMRs in other genomic structural regions(Exon,Intron,Promoter,UTR3,UTR5)was less than the number of low methylated DMRs,and the difference was statistically significant(P?0.05).We compared the average methylation levels of DMR in various genomic structural regions of Mongolian prostate cancer and Han prostate cancer.The results show that the average methylation level of DMR of Mongolian prostate cancer CGI is higher than that of Han prostate cancer.The difference was statistically significant(P?0.05).Mongolian prostate cancer Exon,Intron,Promoter,UTR3,UTR5 average methylation level of DMR in five gene regions was lower than that of Han prostate cancer,and the difference was statistically significant(P?0.05).2.By comparing 3 Mongolian prostate cancer samples with 2 Mongolian normal human samples,we found the following findings:(1)The overall C methylation level of Mongolian prostate cancer genome ranges from 2.52% to 2.65%.CG methylation levels ranged from 74.51% to 77.94%.The overall C methylation level of the Mongolian normal human genome ranges from3.80% to 3.90%;the CG methylation level ranges from 82.46% to 85.74%.The overall C and CG methylation levels of Mongolian prostate cancer genomes are lower than those of Mongolian normal people,and the sample genomes of Mongolian prostate cancer and Mongolian normal people are methylated in all methylated cytosines of CG types.The proportion of cytosine is particularly high,accounting for> 99% of all methylated cytosines,while the proportion of methylated cytosines of CHG and CHH types is very small.(2)Mongolian prostate cancer and Mongolian normal people had significantly higher CG methylation levels than C,CHG,and CHH methylation levels in all genomic regions.Compared with Mongolian normal people,the C methylation level of Mongolian prostate cancer UTR5 was lower than that of Mongolian normal people,and there was a statistical difference(P?0.05).Mongolian prostate cancer remaining regions(Region,Intergenic,Exon,Gene,UTR3,Intron,Promoter)C methylation levels were not statistically different from Mongolian normal people(P> 0.05).The CG methylation levels of Mongolian prostate cancer Exon,UTR3,UTR5,and Promoter were lower than those of Mongolian normal people,which was statistically different(P?0.05).CG methylation levels in the remaining genomic regions(Region,Intergenic,Gene,Intron)of Mongolian prostate cancer were not significantly different from those of Mongolian normal people(P> 0.05).The methylation levels of CHG and CHH in all genomic regions of Mongolian prostate cancer were not significantly different from those of Mongolian normal people(P> 0.05).(3)We analyzed the ratio of C sites(CG,CHG,and CHH)to all methylated C sites in different methylation environments of Mongolian prostate cancer and Mongolian normal humans in different sample genomes.The results show that relative to CHG and CHH,Mongolian prostate cancer and Mongolian normal human genome CG methylation are at high methylation levels.(4)We analyzed the methylation C sites of Mongolian prostate cancer and Mongolian normal human genomes in different methylation environments(high methylation level,medium methylation level,and low methylation level)through Motif analysis.(CG,CHG,and CHH)Is there a preference for base sequences in the9 bp range? The analysis results showed that Mongolian prostate cancer and Mongolian normal human genomes have different base sequences in the 9bp range near different types of methylated C sites in different methylation environments.It is worth noting that,in the genomes of the two populations above,the H bias of CHG is adenine,the first H bias of CHH is adenine,and the second bias of thymine is thymine..(5)We analyzed genomic regions(DMRs)with significantly different methylation levels in the genomes of Mongolian prostate cancer and Mongolian normal humans.The study found that Mongolian prostate cancers and Mongolian normal humans detected a total of 11013 DMRs in all genomes.By analyzing the methylation levels of all DMRs of Mongolian prostate cancer and Han prostate cancer,it was found that compared with Mongolian normal people,the average methylation level of Mongolian prostate cancer DMR was lower than that of Mongolian normal people.Statistical significance(P?0.05).Annotate the genetic structure of all DMRs.The results show that Mongolian prostate cancer and Mongolian normal people have the most DMR annotations to Intron in all genomes,followed by Promoter,and the least DMR annotations to UTR3 and UTR5.We counted the distribution of DMR in the genomic structure of Mongolian prostate cancer and Mongolian normal people.We found that the number of hypermethylated DMRs in all genomes of the above two populations was higher than the number of low methylated DMRs.The difference was statistically significant.(P?0.05).The number of hypermethylated DMRs in other genomic structural regions(Exon,Intron,Promoter,UTR3,UTR5)was less than the number of low methylated DMRs,and the difference was statistically significant(P?0.05).Comparing the average methylation level of DMR in various genomic structural regions of Mongolian prostate cancer and Mongolian normal people,the results show that the average methylation level of DMR of Mongolian prostate cancer CGI is higher than that of Mongolian normal people.The difference was statistically significant(P?0.05).Mongolian prostate cancer Exon,Intron,Promoter,UTR3,UTR5 average gene methylation levels in five gene regions were lower than Mongolian normal people,and the difference was statistically significant(P?0.05).In conclusion(1)Mongolian population(prostate cancer,normal people),Han prostate cancer population has a methylation level of about 3% at the C site,and CG methylation levels are about 80%.The methylation level of CG loci was lower than that of Han prostate cancer and lower than that of normal Mongolian.(2)Mongolian population(prostate cancer,normal people),Han population(prostate cancer),the main methylation pattern is CG site methylation;and the CG site methylation level of the two populations is relatively high methylation Level,while the methylation level of CHG site and CHH site is relatively low methylation level.(3)The methylation level of C site in all genomic regions of Mongolian prostate cancer was lower than that of Han prostate cancer;the methylation levels of CG,CHG and CHH sites in all genomic regions were not significantly different from that of Han prostate cancer.(4)The methylation level of C site in UTR5 region of Mongolian prostate cancer is lower than that of normal Mongolian people;Exon,UTR3,UTR5,and Promoter regions have lower levels of CG methylation than normal Mongolian;CHG sites in all genomic regions There was no significant difference between the methylation level of CHH site and Mongolian normal people.(5)The Mongolian population(prostate cancer,normal people)and the Han population(prostate cancer)have different base sequence preferences in the 9bp range near the CG,CHG,and CHH sites in different methylation environments,but in different methylation environments.In the methylation level environment of all samples,the H partial bias of CHG in all sample genomes is adenine,the first H preference of CHH is adenine,and the second preference is thymine.(6)Compared with Han prostate cancer,Mongolian prostate cancer overall methylation level is lower than Han prostate cancer;Mongolian CGI methylation level is higher than Han prostate cancer.Compared with Mongolian normal people,the overall genome methylation level of Mongolian prostate cancer is lower than that of Mongolian normal people;Mongolian CGI methylation level is higher than that of Mongolian normal people. |
PDF Full Text Request