Typing of 67 SNP Loci on X Chromosome by PCR and MALDI - TOF MS

A set of single nucleotide polymorphisms (SNP) on X chromosome was selected with the aim of forensic identification in Chinese Han population to complement the analysis of autosomal, Y-chromosomal or mitochondrial markers, especially in deficiency cases. 67 forensically relevant X-SNPs were screened in a Chinese Han population sample. Genomic DNA samples extracted from 295 unrelated Chinese Han individuals were typed using three 17-plex and one 16-plex amplification reactions in combination with genetic analysis assisted by massspectrometry based on MassARRAY MALDI-TOF MS platform (Sequenom Inc.). All the investigated loci except rs12849634 were found to be in Hardy-Weinberg equilibrium. A total of 52 of the loci showing independent inheritance and high polymorphisms with minor allele frequency (MAF) above 0.3 were finally screened out. The accumulative exclusion probabilities (CPE) in trio cases and duo cases were above 0.999999. The combined discrimination power (CDP) in female population and male populations were above 0.999999999999999. It is concluded that the panel of informative SNP markers on X chromosome may be used for forensic genetic purposes. The mass spectrometry-based method for X-SNPs profiling was suitable for high-throughput application and could have promising prospects.