Mutational data and population profiling of 23 Y-STRs in three Brazilian populations. (September 2020)

• Record Type: Journal Article
• Authors: Ambrosio, Isabela Brunelli; Braganholi, Danilo Faustino; Orlando, Larissa Barros Muniz; Andrekenas, Natalia Carolina; da Mota Pontes, Isabel; da Silva, Dayse Aparecida; Astolfi-Filho, Spartaco; de Carvalho, Elizeu Fagundes; Cicarelli, Regina Maria Barretto; Gusmão, Leonor
• Is Part Of: Forensic science international. Volume 48(2020)
• Publication Date: 2020-09
• Subjects: Y chromosome -- Mutation rates -- São Paulo -- Rio de Janeiro -- Manaus; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2020.102348
• Languages: English
• ISSNs: 1872-4973

Abstract

Highlights: Haplotype and mutation data are provided for Y-STRs in Brazilian samples. The three studied populations showed high haplotype diversities and low differentiation. Thirty-six mutations were observed in 15 of the 22 Y-STRs analyzed. Loci with GAAA or GATA repeats showed an increase in mutation rate with allele size. An increase in the mutation rate with the father's age was observed. Abstract: Y-chromosomal STRs are important markers in forensic genetics, due to some peculiar characteristics. The absence of recombination makes them a useful tool to infer kinship in complex cases involving distant paternal relatives, or to infer paternal bio-geographic ancestry. The presence of a single copy, being transmitted from father to son, allow tracing mutational events in Y-STRs without ambiguity. For the statistical interpretation of forensic evidences based on Y-STR profiles, it is necessary to have estimates on both mutation rates and haplotype frequencies. In this work, 407 father-son duos from São Paulo and Rio de Janeiro states and 204 unrelated individuals from Manaus were analyzed. Haplotype frequencies and mutation rates for the Y-STRs from the PowerPlex Y23 commercial kit were estimated. Thirty-six mutations were observed in 15 of the 22 Y-STRs analyzed, for an average mutation rate of 3.84 × 10 −3 (95 % CI 2.69 × 10 −3 to 5.32 × 10 −3 ). All mutations in GAAA repeats occurred in alleles with 13 or more uninterrupted units. Mutations in GATA repeats were observed in alleles with 9–17 uninterrupted units. An analysis carried out in different father's age groups showed an increase of 2.48 times the mutation rate in the age group of 40–50 years, when compared to the 20–30 age group, in agreement with the described for autosomal STRs. A high haplotype diversity was found in the three Brazilian populations. Pairwise genetic distance analysis ( FST ) showed no significant differences between the three populations in this study, which were also close to populations with strong European influence. The highest distances among the Brazilian populations were with São Gabriel da Cachoeira, which has a high Native American ancestry.