In the population genomics era, the study of Y-chromosome variability is still of the greatest interest for several fields ranging from molecular anthropology to forensics and genetic genealogy. In particular, mutation rates of Y-chromosomal Short Tandem Repeats markers (Y-STRs) are key parameters for different interdisciplinary applications. Among them, testing the patrilineal relatedness between individuals and calculating their Time of Most Recent Common Ancestors (TMRCAs) are of the utmost importance. To provide new valuable estimates and to address these issues, we typed 47 Y-STRs (comprising Yfiler, PowerPlex23 and YfilerPlus loci, the recently defined Rapidly Mutating [RM] panel and 11 additional markers often used in genetic genealogical applications) in 135 individuals belonging to 66 deep-rooting paternal genealogies from Northern Italy. Our results confirmed that the genealogy approach is an effective way to obtain reliable Y-STR mutation rate estimates even with a limited number of samples. Moreover, they showed that the impact of multi-step mutations and backmutations is negligible within the temporal scale usually adopted by forensic and genetic genealogy analyses. We then detected a significant association between the number of mutations within genealogies and observed TMRCAs. Therefore, we compared observed and expected TMRCAs by implementing a Bayesian procedure originally designed by Walsh (2001) and showed that the method yields a good performance (up to 96.72%), especially when using the Infinite Alleles Model (IAM).

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Rapidly Mutating Y-STRs (RM Y-STRs) were recently introduced in forensics in order to increase the differentiation of Y-chromosomal profiles even in case of close relatives. We estimate RM Y-STRs mutation rates and their power to discriminate between related individuals by using samples extracted from a wide set of paternal pedigrees and by comparing RM Y-STRs results with those obtained from the Y-filer set. In addition, we tested the ability of RM Y-STRs to discriminate between unrelated individuals carrying the same Y-filer haplotype, using the haplogroup R-M269 (reportedly characterised by a strong resemblance in Y-STR profiles) as a case study. Our results, despite confirming the high mutability of RM Y-STRs, show significantly lower mutation rates than reference germline ones. Consequently, their power to discriminate between related individuals, despite being higher than the one of Y-filer, does not seem to improve significantly the performance of the latter. On the contrary, when considering R-M269 unrelated individuals, RM Y-STRs reveal significant discriminatory power and retain some phylogenetic signal, allowing the correct classification of individuals for some R-M269-derived sub-lineages. These results have important implications not only for forensics, but also for molecular anthropology, suggesting that RM Y-STRs are useful tools for exploring subtle genetic variability within Y-chromosomal haplogroups.

In this study, we report novel data on mitochondrial DNA in two of the largest eastern Bantu-speaking populations, the Shona from Zimbabwe and the Hutu from Rwanda. The goal is to evaluate the genetic relationships of these two ethnic groups with other Bantu-speaking populations. Moreover, by comparing our data with those from other Niger-Congo speaking populations, we aim to clarify some aspects of evolutionary and demographic processes accompanying the spread of Bantu languages in sub-Saharan Africa and to test if patterns of genetic variation fit with models of population expansion based on linguistic and archeological data. The results indicate that the Shona and Hutu are closely related to the other Bantu-speaking populations. However, there are some differences in haplogroup composition between the two populations, mainly due to different genetic contributions from neighboring populations. This result is confirmed by estimates of migration rates which show high levels of gene flow not only between pairs of Bantu-speaking populations, but also between Bantu and non-Bantu speakers. The observed pattern of genetic variability (high genetic homogeneity and high levels of gene flow) supports a linguistic model suggesting a gradual spread of Bantu-speakers, with strong interactions between the different lines of Bantu-speaker descent, and is also in agreement with recent archeological findings. In conclusion, our data emphasize the role that population admixture has played at different times and to varying degrees in the dispersal of Bantu languages.

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The precision of the ID Identity Panel kit was assessed on a large set of challenging forensic samples. A threshold of 50 reads for locus call reduces the frequency of sequencing errors. Replicate analyses assure a low/null rate of typing errors. The high number of markers of the kit assures a random match of probability ≤ 1.6 x 10-13 even for the most challenging samples. PCR-MPS of SNP markers is the ideal approach to the analysis of LCN and degraded DNAs.

Objectives: The rarity of familial neuroblastoma (NB) has allowed only a few linkage studies, most of which did not show any evidence of linkage to regions involved in somatic alterations or to genes implicated in other neurocristopathies seldom associated with NB. We screened a highly informative family with recurrent NB by genome-wide linkage analysis aimed at identifying chromosomal regions for NB predisposing genes. Methods: A genome-wide screen was performed using 382 microsatellite markers. Multipoint model-based linkage analysis was carried out under a dominant mode of inheritance for the disease using the ‘affected only’ approach. Results: Our analysis identified two haplotypes co-segregating with the disease on chromosomes 2p and 12p, and yielded maximum lod-score values of 3.01 (p < 0.0001) for markers on both intervals. Conclusions: Evidence of linkage was reported at 16p in North American families, whereas our studies excluded this interval and indicated other loci for disease predisposition, thus confirming the remarkable genetic heterogeneity of NB. These results suggest an oligogenic inheritance in NB involving more loci in genetic determination of the disease.

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