Age prediction is of great importance for criminal investigation and judicial expertise. DNA methylation status is considered a promising method to infer tissue age by virtue of age‐dependent changes on methylation sites. In recent years, forensic scientists have established various models to predict the chronological age of blood, saliva, and semen based on DNA methylation status. However, hair‐inferred age has not been studied in the field of forensic science. In this study, we measured the methylation statuses of potential age‐related CpG sites by using the multiplex methylation SNaPshot method. A total of 10 CpG sites from the LAG3, SCGN, ELOVL2, KLF14, C1orf132, SLC12A5, GRIA2, and PDE4C genes were found to be tightly associated with age in hair follicles. A correlation coefficient above 0.7 was found for four CpG sites (cg24724428 and Chr6:11044628 in ELOVL2, cg25148589 in GRIA2, and cg07547549 in SLC12A5). Among four age‐prediction models, the multiple linear regression model consisting of 10 CpG sites provided the best‐fitting results, with a median absolute deviation of 3.68 years. It is feasible to obtain both human identification and age information from a single scalp hair follicle. No significant differences in methylation degree were found between different sexes, hair types, or hair colors. In conclusion, we established a method to evaluate chronological age by assessing DNA methylation status in hair follicles.

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At present, the planning of 15-minute community-life circle is being actively promoted in China. Taking Baoding City as an example, the status quo of service facilities layout was analyzed based on the POI data. Using the spatial accessibility algorithm, the ranges of 15-minute life circle of more than 1000 communities in Baoding were determined. By calculating the up-to-standard rates of public service facilities in each district, it is found that the allocation of medical facilities and commercial facilities in urban community life circle is relatively perfect, but the allocation of public cultural facilities and pension facilities is obviously inadequate. Based on this, optimization suggestions on the layout of public service facilities in the 15-minute life circle were put forward from three aspects: facilities sharing, function mixing and population structure and activity characteristics differentiation. It not only provides data and technical support for the planning and construction of community life circle in Baoding city, but also provides referable examples and promotable models for the community planning of third-tier cities.

Unbalanced and degraded mixtures (UDM) are frequently encountered during forensic DNA analysis. For example, forensic DNA units regularly encounter DNA mixture signal where the DNA signal from the alleged offender is masked or swamped by high quantities of DNA from the victim. Our previous data presented a new kind of DNA markers that composed of a deletion/insertion polymorphism (DIP) and a SNP and we termed this new kind of microhaplotypes DIP‐SNP (combination of DIP and SNP). Since such markers could be designed short enough for degraded DNA amplification, we hypothesized that DIP‐SNP markers are applicable for typing of UDM. In this study, we developed a new set of DIP‐SNPs with short amplicons which were complement to our prior developed system. The multiplex PCR and SNaPshot assay were established for 20 DIP‐SNPs in a Chinese Han population. The DIP‐SNPs were capable of detecting the minor contributor's allele in home‐made DNA mixture with sensitivities from 1:100 to 1:1000 with a total of 1 –10 ng input DNA. Moreover, this system successfully typed the degraded DNA whether it came from the single source or mixture samples. In Chinese population, the system showed an average informative value of 0.293 and combined informative value of 0.998363862. Our results demonstrated that DIP‐SNPs may serve as a valuable tool in detection of UDM in forensic medicine.

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