The limited application value of SNP-STR markers in the analysis of minor components on imbalanced DNA mixtures
Objective To evaluate the utility of PCR-based SNP-STR typing methods in the analysis of minor components on unbalanced DNA mixtures.Methods SNP-STR fluorescence multiplex PCR typing method was established by ARMS technology.We detected the genotypes of 6 SNP-STR markers in 321 unrelated individuals in the Han Chinese population,and evaluated the genetic polymorphism parameters.We detected(1)the sensitivity of the technique to obtain successful typing in a single DNA sample,(2)the probability of effective information in the analysis of DNA mixtures in two bodies,and(3)the maximum mixing proportion of minor component genotypes in different proportions of DNA mixtures.Results Six SNP-STR fluorescent multiplex PCR techniques yielded a minimum DNA input of 62.5 pg for all genotypes.cSNP-STR genotypes of minor components could be obtained from two body mixed DNA with a mixing ratio of up to 100:1.With the increasing of mixing proportions,the enhanced signal of the major component stutter peak may affected the accurate judgment of the minor component allelic peak.The informative probability of six markers for mixture analysis of Han population in central China was 0.3562.These SNP-STR markers were more discriminative than STR in forensic imbalanced mixture detection.Conclusion SNP-STR markers are more discriminative than STR in the detection of forensic mixed compounds.However,the problem of the major component stutter peak of unbalanced mixtures may limits the utility of SNP-STR markers in the analysis of minor components of unbalanced DNA mixtures.
Unbalanced DNA mixtureSNP-STRMinor componentsMultiplex analysisARMS
NETL
NSTL
万方数据
