Due to its history, with a high number of migration events, the Mediterranean basin represents a challenging area for population genetic studies. A large number of genetic studies have been carried out in the Mediterranean area using different markers but no consensus has been reached on the genetic landscape of the Mediterranean populations. In order to further investigate the genetics of the human Mediterranean populations, we typed 894 individuals from 11 Mediterranean populations with 25 single-nucleotide polymorphisms (SNPs) located on the X-chromosome.

Recently introduced rapidly mutating Y-chromosomal short tandem repeat (RM Y-STR) loci, displaying a multiple-fold higher mutation rate relative to any other Y-STRs, including those conventionally used in forensic casework, have been demonstrated to improve the resolution of male lineage differentiation and to allow male relative separation usually impossible with standard Y-STRs. However, large and geographically-detailed frequency haplotype databases are required to estimate the statistical weight of RM Y-STR haplotype matches if observed in forensic casework. With this in mind, the Italian Working Group (GEFI) of the International Society for Forensic Genetics launched a collaborative exercise aimed at generating an Italian quality controlled forensic RM Y-STR haplotype database. Overall 1509 male individuals from 13 regional populations covering northern, central and southern areas of the Italian peninsula plus Sicily were collected, including both "rural" and "urban" samples classified according to population density in the sampling area. A subset of individuals was additionally genotyped for Y-STR loci included in the Yfiler and PowerPlex Y23 (PPY23) systems (75% and 62%, respectively), allowing the comparison of RM and conventional Y-STRs. Considering the whole set of 13 RM Y-STRs, 1501 unique haplotypes were observed among the 1509 sampled Italian men with a haplotype diversity of 0.999996, largely superior to Yfiler and PPY23 with 0.999914 and 0.999950, respectively. AMOVA indicated that 99.996% of the haplotype variation was within populations, confirming that genetic-geographic structure is almost undetected by RM Y-STRs. Haplotype sharing among regional Italian populations was not observed at all with the complete set of 13 RM Y-STRs. Haplotype sharing within Italian populations was very rare (0.27% non-unique haplotypes), and lower in urban (0.22%) than rural (0.29%) areas. Additionally, 422 father-son pairs were investigated, and 20.1% of them could be discriminated by the whole set of 13 RM Y-STRs, which was very close to the theoretically expected estimate of 19.5% given the mutation rates of the markers used. Results obtained from a high-coverage Italian haplotype dataset confirm on the regional scale the exceptional ability of RM Y-STRs to resolve male lineages previously observed globally, and attest the unsurpassed value of RM Y-STRs for male-relative differentiation purposes.

The identification of human remains is a major challenge in forensic science, particularly in cases of advanced decomposition. Human teeth are among the most resilient tissues to environmental and post-mortem degradation, making them a valuable source of DNA for forensic identification. However, DNA preservation in teeth is influenced by multiple factors that can compromise the success of genetic analysis. Objective: This review analyzes the intrinsic and extrinsic factors affecting DNA preservation in human teeth, focusing on ante-mortem and post-mortem variables rather than the methodological aspects of DNA extraction and analysis. Methodology: A review of the literature was conducted, evaluating studies that assess the impact of biological factors (such as dental structure, pathology, and treatment) and environmental conditions (such as burial environment, temperature, and humidity) on DNA degradation in human teeth. Results: The findings indicate that DNA preservation is significantly influenced by the type of tooth, the presence of dental restorations or pathological conditions, and exposure to environmental factors. While some studies address these variables individually, forensic cases often involve complex interactions among multiple factors, making DNA recovery outcomes unpredictable. Conclusions: The degradation of DNA in human teeth results from a multifactorial process where intrinsic and extrinsic elements interact dynamically. A comprehensive understanding of these factors is essential for optimizing sampling strategies and improving DNA recovery success rates in forensic applications. Future research should aim to develop predictive models that account for these variables, enabling more effective case-specific approaches to forensic DNA analysis.