DNA genetic markers have always played important roles in individual identification, kinship analysis, ancestry inference and phenotype characterization in the field of forensic medicine. DNA methylation has unique advantages in biological age inference, body fluid identification and prediction of phenotypes. The majority of current studies independently examine DNA and DNA methylation markers using various workflows, and they use various analytical procedures to interpret the biological information these two markers present. Integrated methods detect DNA and DNA methylation markers simultaneously through a single experimental workflow using the same preparation of sample. Therefore, they can effectively reduce consumption of time and cost, streamline experimental procedures, and preserve valuable DNA samples taken from crime scenes. In this paper, the integrated detection approaches of DNA and DNA methylation markers on different detection platforms were reviewed. In order to convert methylation modifications to detectable forms, several options were available for pretreatment of genomic DNA, including digestion with methylation-sensitive restriction enzyme, affinity enrichment of methylated fragments, conversion of methylated or unmethylated cytosine. Multiplexed primers can be designed for DNA markers and converted DNA methylation markers for co-amplification. The schemes of using capillary electrophoresis platform for integrated detection add the pretreatment of genomic DNA on the basis of detecting DNA genetic markers. DNA and DNA methylation markers are then integrated by co-amplification. But the limited number of fluorescent options available and the length of amplicons restrict the type and quantity of markers that can be integrated into a panel. Pyrophosphate sequencing also supports integrated detection of DNA and DNA methylation markers. On this platform, due to the conversion of unmethylated cytosine to thymine after treatment with bisulfite, the methylation level of CpG site can be directly calculated using the peak height ratio of cytosine bases and thymine bases. Therefore, the methylation levels and SNP typing can be simultaneously obtained. However, due to the limited read length of sequencing, the detection of markers with longer amplicons is restricted. It is not conducive to fully interpret the complete information of the target sequence. Next-generation sequencing also supports integrated detection of DNA and DNA methylation markers. A preliminary experimental process including DNA extraction, pretreatment of genomic DNA, co-preparation of DNA and DNA methylation library and co-sequencing, has been formed based on the next-generation sequencing platform. It confirmed the feasibility of next-generation sequencing technology for integrated detection of DNA and DNA methylation markers. In field of biomedicine, various integrated detection schemes and corresponding data analysis approaches of DNA and DNA genetic markers developed based on the above detection process.Co-analysis can simultaneously obtain the genomic genetic and epigenetic information through a single analytic process. These schemes suggest that next-generation sequencing may be an effective method for achieving more accurate and highly integrated detection, helping to explore the potential for application in forensic biological samples. We finally explore the impact of interactions between sites and different pretreatment methods on the integrated detection of DNA and DNA methylation markers, and also propose the challenge of applying third-generation sequencing for integrated detection in forensic samples.

ObjectiveTo investigate the genetic polymorphism and structure of 47 autosomal microhaplotypes in the Han population in Changshu City, Jiangsu Province, and to evaluate the forensic efficiencies and forensic parameters. MethodsThe DNA library of unrelated individual samples was prepared according to MHSeqTyper47 kit manual and sequenced on the MiSeq FGx platform. Microhaplotype genotyping and sequencing depth statistics were processed using MHTyper. The genetic information of samples was then evaluated. The fixation index and genetic distance between the Jiangsu Changshu population and the reference populations in the 1000 Genomes Project phase 3 (1KG) were calculated, and forensic parameters were evaluated. ResultsThe fixation index and genetic distance between the Han population in Changshu, Jiangsu, and the CHB (Han Chinese in Beijing, China) reference population in 1KG were the lowest. The effective allele number (A_e) of each locus is also the closest between the two populations. The combined matching probability (CMP) of the Changshu Han population is close to the 5 populations of the East Asian reference super-population in 1KG, which is 1.25×10^-36, and the combined probability of exclusion reached 0.999 999 999 964 1. ConclusionThis study reported the genetic polymorphism and allele frequency of 47 microhaplotypes in a Han population in Changshu City, Jiangsu Province. This information provides a data basis for 47 microhaplotypes in forensic applications. In addition, the polymorphism differences between the 1KG reference population and the Han population in Changshu, Jiangsu were compared, and the genetic structure of 47 microhaplotypes in the Han population in Changshu, Jiangsu was revealed. In general, the reference data of the East Asian super-population in 1KG is more in line with the genetic characteristics of Han population in Changshu, Jiangsu.