| Objective:This paper studies the genetic polymorphism and mutation of 21 STR loci in Han population in Northern Anhui Province.Based on the genetic parameters of forensic science,the application value of STR loci in forensic medicine is evaluated.It provides theoretical basis and reference for the identification of Han population and the identification of parental relationship in Northern Anhui Province.Materials and Methods:(1)Blood samples from 1474 independent individuals of the Han nationality in northern Anhui were collected.The SIFASTR 23 Plex human fluorescent labeled STR complex PCR amplification system was used,and 21 STR loci were isolated by ABI3130XL genetic analyzer capillary electrophoresis.Gene Mapper ID 3.2 software was used for DNA typing,and genotyping results of 21 STR loci were obtained.HWE test was performed and genetic parameters of H,PM,DP,PE,PIC,TDP,CPE were analyzed on 21STR loci using Modified-Power States softwareby Modified-Power States software.(2)19STR loci,which are required to be tested in Technical Specification for Parenthood Identification,were selected to evaluate and analyze the differences in gene frequency and number of alleles between the Han population in northern Anhui and Shandong,Henan and Jiangsu provinces.(3)The detection kit Microreader TM21 Direct ID System,Si Fast R 23 Plex and AGCU EX22 human fluorescent labeled STR complex amplification System were used respectively.PCR complex amplification,product electrophoresis separation and laser scanning analysis were performed.The genotyping results of STR loci were obtained.The mutation rate and the number of mutation steps of autosomal STR loci in the Han population in northern Anhui were statistically analyzed with different kits,and the corresponding sex source and mutation mode of the mutant gene were analyzed.Meanwhile,the mutation rate of the autosomal STR loci in the Han population in Henan was compared with that of the corresponding loci.Results:(1)The 21 autosomal STR loci of 1474 individuals from the Han population in northern Anhui Province,except for D21S11 and D6S1043,all of them had high coincidence with Hardy-Weinberg equilibrium.A total of 280 alleles were obtained by 21 STR loci test from 1474 samples of Han population screened in northern Anhui.The frequency of alleles ranged from 0.0003 to 0.5315,the heterozygosity(H)ranged from 0.6242 to 0.9050,and the matching probability(PM)ranged from 0.0127 to 0.1752.Individual recognition ability(DP),non-paternal exclusion probability(PE),polyphic information content(PIC)and typical paternity index(TPI)were 0.7988?0.9873,0.3210?0.8058,0.5721?0.9104,and 1.3306?5.2628.Among them,the largest H and PE is Penta E and the smallest is TPOX,indicating that the genetic polymorphism of 21 loci is the highest Penta E and the lowest is TPOX.Except for five loci,such as D3S1358,the other loci were all high discriminant indexes.The value of heterozygosity corresponding to five loci,such as D3S1358,ranged from 0.591 to 0.755,and the individual recognition rate ranged from 0.764 to 0.897,indicating a moderate performance in identification ability.The TDP and CPE of 21 STR loci were 0.99999999.In conclusion,these 21 loci have good discriminative ability.(2)Among the 19 STR loci required to be detected in the Technical Specification for Parenting Rights Identification,254 alleles,209 alleles,185 alleles and 325 alleles were detected in the Han population in northern Anhui,Shandong,Henan and Jiangsu provinces,respectively.The number and frequency of alleles in different STR loci were compared.Taking D7S820 locus as an example,allele 9.3 was detected in the Han population in northern Anhui,but not in the Han population in Shandong,Henan and Jiangsu.The gene frequency of D7S820 locus 13 was 0.0444 in the Han population in northern Anhui,and0.0317,0.0385 and 0.0384 in the Han population in Shandong,Henan and Jiangsu,respectively.These results indicated that there were some differences in the number and frequency of alleles in the same locus in different regions.(3)Microreader TM21 Direct ID System kit was used to detect 7671 paternity identification samples in northern Anhui,and 127 mutations were found in 17 mutated STR loci,and the mutation rate was all less than 0.2%.The mutation rate of D21S11 locus was the highest,while D6S1043,Pentad and TPOX had no mutation.A total of 9561 samples were detected by the combination of Microreader TM21 Direct ID System kit and Si FASTR 23 plex kit.The mutation rate of 19 STR loci in Henan was compared with that of 19 STR loci.The mutation rate of D13S317 locus was 0.0406%in the Han population in northern Anhui,while no mutation was detected in this locus in 3011 cases of Han people in Henan.Through data analysis,it was found that the mutation rate of each locus was different.Among the 42cases of mutations detected by Microreader TM21 Direct ID System kit,39 cases were one-step mutations,with the highest incidence of one-step mutations.The paternity test with SIFASTR 23 Plex kit showed 64 mutations,including 59 one-step mutations.Nine mutation cases and nine mutated STR loci were found in paternity samples detected by AGCU EX22,with mutation rates ranging from 0.062%to 0.123%.Among the 106 mutations detected by Microreader TM21 Direct ID System kit and Si FASTR 23 plex kit,89 were from the male parent and 17 were from the female parent,so the ratio of paternity to maternal mutation was5.24:1.The paternal mutation was significantly higher than the maternal mutation.Conclusion:(1)In the Han population in Northern Anhui Province,21 loci corresponding to sifastr 23 plex detection system can be balanced with Hardy Weinberg,and have a very large amount of polymorphic information.In these loci,the non paternal exclusion rate and individual recognition ability are high,which has a strong application value in forensic science.(2)The results showed that alleles and allele frequencies were not exactly the same in different regions of the population,to obtain and use the STR locus database of local population to further improve the accuracy of paternity identification results,the gene frequency obtained in this study can be used for paternity identification of Han population in northern Anhui,so as to obtain more accurate identification results.(3)The mutation rate of STR loci,the number of steps and the origin of mutation sex in the northern Anhui Han population obtained in this study are consistent with the existing research results,and can be applied to the identification of paternity.In conclusion,the results obtained in this study can serve as the theoretical basis for paternity identification of the Han population in northern Anhui,and lay a foundation for the establishment of DNA database of the Han population in northern Anhui.The results of STR locus mutation analysis not only enrich the genetic information of the Han population in this area,but also provide a relatively reliable basis for the determination of suspected mutations in the identification process of paternity,so as to improve the reliability of identification conclusions. |
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