Application Value of Non-COIDS STR and X-SNP Markers for Diffiuclt Relationship Testing
|Keywords||STR X-Chromosome SNP AGCU21+1 Kit MALDI-TOF|
Objective: Through investigating the genetic polymorphisms 26 autosomal non-CODIS STR loci in Chinese Han Population and establishing the MALDI-TOF MS platform for 67 SNPs on X-Chromosome to provide methods for special cases such as mutational cases、special excluded cases、the judgement of relationships of grandmother to granddaughter and half-sib sisters with the same father.Methods: The polymorphisms of 21 autosomal non-CODIS STR loci in Chinese Han population were detected by the AGCU 21+1 STR kit .The genetic parameters of them were calculated; The multiplex-PCR system of the six autosomal non-CODIS STR loci was established to detect their polymorphisms in Chinese Han population, and genetic parameters of them were calculated. Application Value of 26 STR loci was investigated through applying in practical cases . Using The MALDI-TOF technique to detect the 67 SNPs on X-Chromosome, then to investigate their polymorphisms in Chinese Han population、genetic parameters and linkage information.Results :The 26 non-CODIS STR loci were polymorphic in Han population with ideal genetic parameters. Allele frequency distributions of the 26 non-CODIS STR loci did not statistically deviated from the laws of Hardy-Weinberg equilibration. The cumulative exclusionary power(CPE) of trios-testing was 0.999999996, the CPE of duo-testing was 0.99998467, and the cumulated discrimination power(CDP)was 0.99999999999999999999999997. There were 66 X-SNPs following Hardy-Weinberg equilibration in all of 67 sites, and 3 SNPs’low allele frequency were below 0.1, and 8 pairs SNPs existed close linkage. Finally we got 56 X-SNP with high information. The CDP in females reach 0.999999999999999999999985,The CDP in males reach 0.999999999999977,the CPE of trios-testing was 0.999999999987, the CPE of duo-testing was 0.999999765。Conclusion : The 26 non CODIS STR loci are highly polymorphic. They can be effectively used in personal identification and paternity testing. They can also be used as important supplementary loci in difficult paternity testing cases. The genotyping of X-SNPs by MALDI-TOF MS technology was accurate and reliable. The selected 56 X-SNPs are highly polymorphic, their CDP and CPE can been able to satisfy the requirement of forensic science, and provide new methods for special paternity testing.