Y-chromosomal Short Tandem Repeat Research Articles

Forensic parameters and genetic structure based on Y-chromosome short tandem repeats in Lesotho populations

Lesotho is a landlocked country with approximately 2.2 million inhabitants. Over 97% of the population is represented by the Southern Sotho people (Sotho-Tswana group), followed by a number of minorities mostly from the Nguni language group. In this study we investigated the patterns of genetic variation and report genetic diversity, forensic parameters and novel allele variations in 938 unrelated Bantu males. Population pairwise comparisons identified high affinities between the Xhosa and the Vundle, while the largest genetic distance was observed between the Vundle and the Baphuthi ethnic groups (Rst = 0.14878). A high level of genetic differentiation between populations was observed considering culture and language affiliations as opposed to geographic distance.

Y chromosome sequence variation of common forensic STR markers and their flanking regions among Polish population

Y-chromosome STR markers’ analysis is widely used as a procedure with examination of sexual assault cases, kinship cases and identification of human remains. At present massively parallel sequencing (MPS) technology proves to be reliable method in analysis of DNA mixtures or low quality of DNA samples. In cases of frequent Y-STR haplotypes, sequence analysis of an allele and flanking region also gives a chance to distinguish microhaplotypes of the samples. In this study authors investigated DNA sequence variability within the Y-STR markers in polish population (reference samples and bone samples). MPS was carried on with Illumina’s ForenSeq kit on the MiSeq FGx instrument. Revealed microhaplotypes and their frequency differ between markers. Some of the analyzed sequences showed no variability in the analyzed set of samples. Confronting the population data with the case samples showed that this type of information can significantly improve kinship calculation and mixture analysis.

Mutation rates of six Y-chromosomal STR loci estimated from 210 pedigrees in Chinese Han population

The Y-chromosomal short tandem repeats (Y-STRs) with low mutation rates as slowly mutating (SM) Y-STRs could be used to refine the construction of phylogenetic trees in evolutionary research. Six Y-STR markers (DYS388, DYS426, DYS461, DYS485, DYS525 and DYS561) were from the previously published paper and considered as SM Y-STRs. Here, we investigated the six Y-STRs from 210 pedigrees in Chinese Han population in Henan province, covering an overall number of 8178 meiotic transfers. The number of mutations of the six Y-STRs ranged from 0 (DYS388 and DYS426) to 12 (DYS561), resulting the observed mutation rates spanned from 0 (95% credible interval [CI], 0∼2.196 × 10−3) to 8.804 × 10−3 (95% CI, 4.557 × 10−3∼1.533 × 10−2). According to the results, only DYS388 and DYS426 could be classified as SM Y-STRs in the Chinese Han population. Although these results will replenish the data of Y-STR mutations as well as be important for paternal genealogy identification, kinship analysis, and phylogenetic tree reconstruction, the mutation rates of the six Y-STRs were significantly different among different populations, which we need to pay attention to in future studies.

Assessment of autosomal and male DNA extracted from casework samples using Casework Direct Kit, Custom and Maxwell 16 System DNA IQ Casework Pro Kit for autosomal-STR and Y-STR profiling

Short repetitive regions in autosomal and Y chromosomes known as short tandem repeats (STRs) are currently used for DNA profiling in crime investigations. However, DNA profiling requires a sufficient quality and quantity of DNA template, which is often not obtained from trace evidence or degraded biological samples collected at the scene of a crime. Here, we assessed autosomal and male DNA components extracted from crime scene and mock casework samples using the Casework Direct Kit, Custom and compared the results against those obtained by extraction of matching samples using well-established Maxwell 16 System DNA IQ Casework Pro Kit. The quantity and quality of extracted DNA obtained using both Casework Direct Kit, Custom and Maxwell 16 System DNA IQ Casework Pro Kit were analyzed using PowerQuant Systems followed by autosomal and Y-chromosome STR profiling using GlobalFiler Express PCR Amplification Kit and PowerPlex Y23 System, respectively. Our results showed that the Casework Direct Kit and Maxwell 16 DNA IQ Casework Pro Kit have more or less equal capacity to extract inhibitor free DNA, but that the latter produces slightly better quality and more DNA template and subsequently higher numbers of STR allele calls for autosomal and Y-STR analyses. Nonetheless, the Casework Direct Kit, Custom is the quicker and cheaper option for extraction of good, clean DNA from high content material and might best be used for extraction of reference samples. Such reference DNA samples typically come from buccal swabs or freshly drawn blood. So, in general, they can confidently be expected to have a high nucleic acid content and to be inhibitor-free.

Sequence characterization of microvariant alleles at DYS627 and DYS458

Y chromosome short tandem repeats (Y-STRs) have been widely used in genetic applications and forensic casework. Recently, we found two intermediate alleles, the DYS627 allele 24.1 and the DYS458 allele 15.3, from Chinese Han population. The two allelic variants have not been recorded by the YHRD database. We have examined the molecular structure of these allelic variants by Sanger sequencing. The results showed that this intermediate allele at DYS627 was confirmed as 24.1, the sequence of which showed a base “A” insertion in the 13th repeat unit, and the intermediate allele at DYS458 was confirmed as 15.3, the sequence of which showed a base “G” deletion in the 12th repeat unit. This may be important for individual identification and paternal kinship testing. Besides, more allelic variants detected can be enriched in the Y-STR database.

Parallel sequencing of 48 Y-chromosome STR and SNP markers

Over the last decade, massively parallel sequencing (MPS) has been rapidly developed, bringing many advantages to forensic genomics. It could simultaneously target multiple genetic markers including short tandem repeats (STRs), insertion and deletion polymorphisms (InDels), and single nucleotide polymorphisms (SNPs). In this study, we developed an assay which can simultaneously sequence 22 Y-STRs and 26 Y-SNPs on the MiSeq FGx™ Forensic Genomics System (Illumina, Inc., San Diego, USA). The primers of the markers were designed using the online DesignStudio (Illumina). Subsequently, DNA libraries were established with the TruSeq Amplicon method. For the pilot study, we sequenced 25 unrelated Chinese Han males. A total of 125 sequence-based alleles were observed at the 22 Y-STR loci, with the average depth of coverage (DoC) ranging from 314.9 x to 637.7 × . For the concordant study, the sequencing results of these samples were fully consistent with genotypes called via capillary electrophoresis (CE). For the SNPs, a preferable performance was observed with the average DoC of 836.5 × . However, inter-locus imbalance was observed at some of the markers, which needs substantial improvement of the primer pool. In general, this customized Y-chromosome STR and SNP panel on the MiSeqFGx™ Forensic Genomics System can provide an effective solution for these markers on Y chromosome, which may allow more forensically relevant information to be obtained from limited forensic materials, such as those from sexual assault and rape cases. Besides, it could also facilitate the forensic practices including paternity testing, genetic determination of pedigree and inter-population migration integration.

Is it reliable to use paraffin embedded tumor tissues as biological evidence in parentage cases?

Short tandem repeats (STR) are reliable markers used for forensic identification and paternity testing. In some cases, histological paraffin blocks containing malignant cells can be used for STR typing in identification and paternity. DNA profiling and result interpretation with these samples often becomes a challenging job. The malignant tissues may show preferential amplification, loss of heterozygosity, and microsatellite instability.Due to the suspected paternity case, two paraffin blocks were sent for DNA analysis by Court of Justice. Pathology report of the paraffin blocks have shown that they contain lung cancer tissues taken with bronchoscopy. After extracting DNA with silica based method from the samples taken from different parts of these two blocks, 21 autosomal STR loci and 17 gonosomal STR loci were studied.When we have compared the STR profiles of son and his alleged father, Y-chromosomal STR loci matched fully. But for 2 of the 21 autosomal STR loci were found mismatches in father-son comparing. These two mismatched loci have been homozygous in alleged father. Moreover, 10 of 21 autosomal loci have shown homozygosity, and at one locus D16S539 has three alleles. While increased homozygosity in FFPE sample of alleged father has increased the paternity index, mismatched loci have lessened it in our model with mutations but without dropout.These results suggest that great care and proper statistical model should be taken in the evaluation of the DNA typing results obtained from clinical cancerous specimens, in particular when no other reference samples containing normal tissue are available.

RETRACTED: Population genetics of 24 Y‐STR loci in Chinese Han population from Jilin Province, Northeast China

BackgroundIt is meaningful to expand the available population information on forensic medicine and to investigate the genetic characteristics of Han population from Jilin Province, Northeast China.MethodsIn this study, we investigated the genetic characteristics of 24 Y‐chromosomal short tandem repeat (STR) loci in 1,088 unrelated Chinese Han male individuals from Jilin Province, using DNATyperTM Y24 amplification kit. Additionally, we performed the population comparison between the Jilin population and the other nine reported populations based on the Y‐STR genotyping haplotypes.ResultsA total of 1,067 different haplotypes were found from 1,088 unrelated individuals, of which 1,046 were unique and 21 were shared by two individuals. The gene diversity values of 22 loci ranged from 0.3870 (DYS391) to 0.9668 (DYS385ab). The random match probability was 0.0010 with the discrimination capacity of 0.9807. Population comparison showed that there were minor differences compared to Beijing Chinese Han, China Manchu, Gansu Chinese Han, and Jiangsu Chinese Han, but major differences with respect to the populations of Guangdong Chinese Han, Yunnan Chinese Han, China Hui, China Korean, and China Tibetan.ConclusionOur results showed that the 24 Y‐STR loci in Jilin Han population are valuable for forensic application and human genetics.

Evaluation of rapidly mutating Y-STRs in Pakistani population

Y-chromosomal Short Tandem Repeats have been widely used in forensic investigations, identification of males for criminal justice purpose and population genetics. Commercially available Y-STRs kits allow the identification of male pedigrees and has a limited application in forensic genetics because of its limitation in differentiating closely related male individuals. Recent research with the Rapidly Mutating Y-STRs (RM Y-STRs) have revealed that these loci deliver significantly higher discrimination capacity and haplotype diversity in worldwide populations when compared with the conventional Y-STRs. Although a number of RM Y-STRs have found their way in most updated commercial kits, there are still some loci that are not yet used in such kits. The aim of this study is to develop RM Y-STR haplotypes frequency database for the Pakistani population, in order to appraise the resolution power of these loci. A total of 212 unrelated males from the Pakistani population were typed with 13 RM Y-STRs which comprise DYF399S1, DYF387S1, DYS570, DYS576, DYS518, DYS526a + b, DYS626, DYS627, DYF403S1a + b, DYF404S1, DYS449, DYS547 and DYS612. 211 unique haplotypes were identified, out of which 1 haplotype was shared between two individuals, accounting for 0.9952 discrimination capacity (DC). Haplotype diversity was found to be 0.999925. Gene diversity (GD) values of all the loci were higher than 0.5, where the highest GD values were observed at DYF399S1, DYF403S1a and DYF404S1; with values of 0.99419, 0.98252 and 0.93061 respectively. Results of our study revealed that these 13 RM Y-STRs produced significantly stronger discriminatory power in Pakistani populations.

Population genetics of 25 Y-STR loci in Chinese Han population from Liaoning Province, Northeast China

In this study, we investigated the genetic characteristics of 25 Y-chromosomal short tandem repeat loci in 305 unrelated Chinese Han male individuals from Liaoning Province, using AmpFISTR® Yfiler® Plus amplification kit. A total of 293 different haplotypes were observed at the 25 Y-STR loci; among them, 281 were unique and 12 were occurred twice. The overall haplotype diversity was 0.9997 and the discrimination capacity was 0.9607. The gene diversity values ranged from 0.4525 (DYS391) to 0.9617 (DYS385). Population relationships between our data and other published populations were measured by Rst and visualized in two multi-dimensional scaling plots. The results showed that the 25 Y-STR loci in Liaoning Han population are valuable for forensic application and human genetics.

Development of a new 17 Y-STRs system using fluorescent-labelled universal primers and its application in Shanxi population in China

Y-chromosomal short tandem repeats (Y-STRs) polymorphisms are useful in forensic identification, population genetics and constructing of human structures. Increasing the number of Y-STRs and their polymorphism will drastically narrow down the matching number of genealogy populations or pedigrees when searching against a forensic DNA databank. In this study, we develop a system containing 17 complementary Y-STRs that are compatible and reinforce the current commercially available Y-STR kits. This system was constructed by multiplex PCR with expected size of 126bp-400bp using home-made universal primers labeled by different fluorescence (DYS715, DYS709, DYS716, DYS713, DYS607, DYS718, DYS723, DYS708, DYS714, DYS712, DYS717, DYS721, DYS605, DYS719, DYS726, DYS598 and DYS722). The genetic data were obtained from 394 individuals in Shanxi province, China. The Y-STR system has 131 haplotypes and high discrimination power is 1. In conclusion, our study provides a robust, sensitive and cost-effective genotyping method for human identification, which is beneficial for narrowing the searching scope when applying to the genealogy searching with Y-STR DNA databank.

Completely automated interpretation of reference samples

Inspired by fully continuous interpretation a completely automated interpretation workflow for reference samples was implemented in our lab. It's based on a quite simple model, which includes DNA amount and degradation as well as backward and forward stutters. The current implementation can handle CE results of any number of replicates, even from different autosomal or Y-chromosomal STR kits. Results, lessons learned in a first set of test series and potential future extensions are discussed.

Genetic Structure Analysis of Y-Chromosome STR and SNP in Population of Wujiang Area, Suzhou City.

Objective To analyze the genetic phenotypes of Y-chromosome STR and SNP in Han male population of Wujiang area, Suzhou City and explore the genetic structure of population of Wujiang area for further examination of regional-specific Y-SNP genetic markers ancestor haplogroups. Methods Blood samples of 472 Wujiang area Han males were randomly collected and genotyped by YfilerTM Plus PCR Amplification Kit. The allele frequencies and haplotype frequencies of each locus were obtained using the direct calculation method. Y-SNP haplogroups of each sample were estimated using Y-Predictor software and verified through experiments by amplification refractory mutation system-polymerase chain reaction （ARMS-PCR）. Results A total of 453 haplotypes were found in the 27 Y-STR genetic markers in 472 Han males of Wujiang area. The haplotype diversity （HD） was 0.997 696 93, among which, the highest gene diversity （GD） value was DYF387S1a/b （GD=0.953 1） and the lowest was DYS438 （GD=0.321 8）. Based on genotyping data of 27 Y-STRs and 472 samples, 132 haplogroups from C, D, N, O and Q, etc downstream Y-SNP haplogroups were estimated and then verified through experiments. Conclusion This study is based on Y-chromosome STR haplotypes, and predicts Y-SNP haplogroups by Y-Predictor software, then uses ARMS-PCR to verify. Y-SNP genetic markers were introduced to achieve precise analysis of the genetic structure of male families in population of three towns in Wujiang area.

DNA Testing Reveals the Putative Identity of JB55, a 19th Century Vampire Buried in Griswold, Connecticut.

In 1990 in Griswold, Connecticut, archaeologists excavated a burial found in a “skull and crossbones” orientation. The lid of the 19th century coffin had brass tacks that spelled “JB55”, the initials of the person lying there and age at death. JB55 had evidence of chronic pulmonary infection, perhaps tuberculosis. It is possible that JB55 was deemed a vampire due to his disease, and therefore had to be “killed” by mutilating his corpse. In an attempt to reveal the identity of JB55, DNA testing was performed. Ancestry informative single nucleotide polymorphism (SNP) analysis using the Precision ID Ancestry Panel indicated European ancestry. A full Y-chromosomal short tandem repeat (Y-STR) profile was obtained, belonging to haplogroup R1b. When the Y-STR profile was searched in the publicly accessible FamilyTreeDNA R1b Project website, the two closest matches had the surname “Barber”. A search of historical records led to a death notice mentioning John Barber, whose son Nathan Barber was buried in Griswold in 1826. The description of Nathan Barber closely fits the burial of “NB13,” found near JB55. By applying modern forensic DNA tools to a historical mystery, the identity of JB55 as John Barber, the 19th century Connecticut vampire, has been revealed.

Population background exploration and genetic distribution analysis of Pakistan Hazara via 23 autosomal STRs

Background: Short tandem repeats (STRs) have gained considerable attention in family search (Y-chromosomal STRs), complex paternity identification (X-chromosomal STRs), routine forensic personal identification (autosomal STRs) and population genetics.Aim: To explore the forensic characteristics of 23 autosomal STRs included in the Huaxia Platinum system in the South Pakistan Hazara population and investigate the genetic similarities and differences between Hazara and 54 worldwide reference populations.Subjects and methods: Variation of the 23 autosomal STRs included in the Huaxia Platinum system was first investigated and reported in a sample of 261 Quetta Hazara in Balochistan Province, Southwest Pakistan.Results: The combined power of discrimination is 0.999999999999999999999999999 and combined power of exclusion is 0.99999999989596 in Quetta Hazara. Comprehensive population comparisons between Hazara and another 13 Eurasian populations based on genotype data, as well as between Hazara and 54 worldwide populations based on the allele frequency distribution, were conducted. Multidimensional scaling plots, principal component analysis, and neighbour-joining phylogenetic trees consistently demonstrated that Pakistan Hazara harbours close affinities with neighbouring Turkic-speaking populations. Model-based genetic structure analysis further suggests that Quetta Hazara derives about half its ancestry directly from the East Asians.Conclusion: Twenty-five forensic-related markers included in the Huaxia Platinum system can be used for forensic practice in the Central Asia Hazara population. Quetta Hazara has a close genetic relationship with the Turkic-speaking populations of Uyghur and Kazakh. Further whole-genome sequencing of Hazara needs to be conducted to validate the observed genetic structure and reconstruct the fine-scale population history of Hazara.

Genetic structure and forensic characteristics of Saraiki population from Southern Punjab, Pakistan, revealed by 20 Y-chromosomal STRs.

Pakistan harbors more than 18 major ethnic groups which speak 60 different languages. People speaking Saraiki languages are known as Saraiki or Multani. They are mainly residents of Southern Punjab including Multan, Dear Ghazi Khan, Rajanpur, and Rahim Yar khan. Here, we reported the data of 20 Y-chromosomal short tandem repeats (Y-STRs) genotyped with the Goldeneye® 20Y kit in 154 unrelated Saraiki individuals. We observed 141 different haplotypes on 20 Y-STR loci and the gene diversity (GD) ranged from 0.6566 (DYS448) to 0.9538 (DYS385a, b). The overall haplotype diversity was 0.9989 at 20 Y-STRs loci. Furthermore, we performed population genetic analyses by including data from 26 other South Asian populations. The presented haplotype data was recently included in the Y-Chromosome Haplotype Reference Database (YHRD) for future forensic and other usage.

Genetic polymorphism and population structure of Torghut Mongols and comparison with a Mongolian population 3000 kilometers away

Mongolians played a pivotal role in shaping the culture and genetic architecture of modern Eurasia through the rapid expansion of the Mongol Empire in the 13th century. While the historical aspects of the Mongolian Empire are well documented, research on the genetic variations among Mongolian populations is still insufficient. In this study, we examined the genetic diversity of 70 Torghut Mongols residing in the Ili region of China compared with 88 Jalaid Mongols residing 3000 km away. Over 200 forensically relevant genetic markers, including autosomal short tandem repeats (A-STRs), X chromosomal STRs (X-STRs), Y chromosomal STRs (Y-STRs), identity-informative single nucleotide polymorphisms (iiSNPs), ancestry-informative SNPs (aiSNPs), and phenotype-informative SNPs (piSNPs), were genotyped to uncover the genetic polymorphism of the Torghut Mongols. The STR genotyping results showed that 80 alleles (39 A-STRs, 25 Y-STRs, and 16 X-STRs; 14.4% of 554 alleles) identified in Torghut Mongols were not identified in Jalaid Mongols, while 155 alleles (84 A-STRs, 59 Y-STRs and 12 X-STRs; 24.6% of 630 alleles) identified in Jalaid Mongols were not observed in Torghut Mongols. Calculation of the forensic parameters demonstrated that the STRs and SNPs analyzed here could be employed in forensic applications. Interpopulation comparisons via principal component analysis (PCA), phylogenetic tree, and STRUCTURE analysis showed that the two Mongolian populations were closely related by their genetic background, although genetic differences were also discovered. When both the sequence-based A-STRs and iiSNPs were included in the STRUCTURE analysis, the Torghut population was more similar to the Uyghur population than to Jalaid Mongols, indicating certain population structure differences between the two Mongolian populations. The Y-DNA haplogroup prediction showed that although haplogroup C (C2-M217) was dominant in both Mongolian populations, haplogroup O2-M122 was rarely presented in Torghut Mongols, which differentiated the Torghut Mongols from the other Mongolian populations. This study not only uncovered the genetic features of the two Mongolian tribes, providing valuable frequency data for forensic applications, but the genetic patterns of the two Mongolian populations also provide a genetic evidence that the Torghut Mongols may have developed via the gradual intermixing of nomadic groups of Mongol and Turkic origin, as recorded in historical records. This study also highlighted the importance of building regional reference databases that consider both ethnic and geographic location information, instead of a more universal reference database, for forensic applications.

Forensic characteristics and genetic analysis of both 27 Y-STRs and 143 Y-SNPs in Eastern Han Chinese population

Y-chromosome short tandem repeat (Y-STR) and Y-chromosome single nucleotide polymorphism (Y-SNP) frequency distributions provide resources for assessment of male population stratification among world-wide populations. Currently, the Y-STR Haplotype Reference Database (YHRD) contains numerous Y-chromosome haplotype profiles from various populations and countries around the world. However, for many of the recently discovered and already phylogenetically mapped Y-SNPs, the population data are scarce. Herein, the typing of 27 Y-STRs (Yfiler Plus) and 143 Y-SNPs (self-designed Y-SNP panel) was performed on 1269 unrelated males from 11 Han Chinese populations. Haplogroup O-M175 was the most predominant haplogroup in our Han Chinese data, ranging from 67.34% (Henan Han) to 93.16% (Guangdong Han). The highest haplogroup diversity (0.967056) was observed in Heilongjiang Han, with a discrimination capacity (DC) value of 0.3723. The number of alleles at single-copy loci varied from 2 for DYS391 (Guangdong Han) to 16 for DYS518 (Henan Han). For the majority of the populations (8/11), both the haplotype diversity and DC values are 1.0000. Furthermore, genetic differentiations were observed between Northern and Southern Han Chinese. These genetic differences were mainly reflected in haplogroup distribution and frequency, and they were confirmed by statistical analysis.

Genetic analysis of 50 Y-STR loci in Dong, Miao, Tujia, and Yao populations from Hunan.

To investigate the genetic polymorphism of Y chromosome short tandem repeat (Y-STR) loci in Dong, Miao, Tujia, and Yao minority populations from Hunan Province, China. Fifty Y-STRs (DYS392, DYS389I/II, DYS447, DYS438, DYS527, DYS645, DYS596, DYS391, DYS456, DYS19, DYS593, DYS448, DYS627, DYS557, DYS437, DYS481, DYS533, DYS390, DYS385, DYF387S1, DYS460, DYS393, Y_GATA_H4, DYS439, DYS635, DYS444, DYS643, DYS549, DYS576, DYS570, DYS458, DYS449, DYS518, DYS531, DYS630, DYS622, DYS552, DYS510, DYS459a/b, DYS446, DYS443, DYS587, Y_GATA_A10, DYS520, DYS522) were analyzed for 2553 unrelated healthy male individuals from Hunan (643 Dong males, 666 Miao males, 633 Tujia males, 611 Yao males) using AGCU Y37 and AGCU Y SUPP STR amplification system. There were 624 different haplotypes in 643 unrelated Dong males, 662 in 666 unrelated Miao males, 627 in 633 unrelated Tujia males, and 587 in 611 unrelated Yao males. The haplotype diversities of Dong, Miao, Tujia, and Yao were determined as 0.999879, 0.999982, 0.999970, and 0.999860, respectively. Analysis of molecular variance (AMOVA) tests demonstrated that genetic distance between Miao and Tujia was the smallest (0.0003), while the genetic distance between Dong and Yao was the largest (0.0252). The 50 Y-STR loci in the four minority populations from Hunan Province revealed a highly polymorphic genetic distribution, which showed a high potential for population genetics and forensic practice.

Estimating Y-Str Mutation Rates and Tmrca Through Deep-Rooting Italian Pedigrees

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).