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Int J Legal Med (2012) 126:327–330 DOI 10.1007/s00414-011-0629-7

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Development of two multiplex PCR systems for the analysis of 14 X-chromosomal STR loci in a southern Brazilian population sample
Larissa Siqueira Penna & Fernanda Gamio Silva & Patricia Hartstein Salim & Gisele Ewald & Mariana Jobim & José Antônio de Azevedo Magalhães & Luiz Fernando Jobim

Received: 15April 2011 / Accepted: 26 September 2011 / Published online: 15 October 2011 # Springer-Verlag 2011

Abstract We developed two multiplex systems for the coamplification of X-chromosomal short tandem repeats (STRs). X-Multiplex 1 consisted of DXS6807, DXS6800, DXS7424, DXS101, GATA172D05 and HPRTB and XMultiplex 2 consisted of DXS8378, DXS9898, DXS6801, DXS6809, DXS6789, DXS7133, DXS8377 andDXS7423. In addition, we present allele frequencies for these loci in a south Brazilian population comprising 124 females and 141 males and haplotype frequencies of linked markers for males. Hardy–
Electronic supplementary material The online version of this article (doi:10.1007/s00414-011-0629-7) contains supplementary material, which is available to authorized users. L. S. Penna : P. H. SalimPostgraduate Program in Medicine, Medical Sciences, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil F. G. Silva : G. Ewald : M. Jobim : L. F. Jobim Department of Immunology, Hospital de Clínicas, Porto Alegre, Brazil J. A. A. Magalhães Department of Gynecology and Obstetrics, Hospital de Clínicas, Porto Alegre, Brazil L. F. Jobim Department of Internal Medicine,Faculty of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil L. S. Penna (*) : L. F. Jobim (*) Serviço de Imunologia, 2°andar, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2350, Bairro Bom Fim, CEP 90035-903 Porto Alegre, RS, Brazil e-mail: larisp@sinos.net e-mail: ljobim@hcpa.ufrgs.br

Weinberg equilibrium (HWE) was tested in the female sample and no significantdeviations were found after applying Bonferroni’s correction. Linkage disequilibrium (LD) tests were performed for all pairs of loci and three significant results, out of 91 pairwise comparisons, were obtained. We did not find any evidence of linkage disequilibrium between close or linked markers. The power of discrimination in females (PDF) varied between 0.832 for DXS6801 and 0.987 for DXS8377.DXS6801 was the least informative marker (PIC=0.605), while DXS8377 was the most polymorphic (PIC=0.911), followed by DXS101 (PIC=0.872). Genetic distances were estimated for each STR marker applying the calculation of FST between our total sample and other studies from Brazil, Europe, Asia and Africa. The most distant populations were Japan, Korea, China, Ghana and Uganda. Keywords X-chromosome .STRs . Population data . Rio Grande do Sul . Brazil

Introduction Autosomal and Y-chromosome short tandem repeat (STR) markers have been studied and widely applied as an effective tool for forensic analysis and human identification [1, 2]. In the last few years, X-chromosome has been the focus of several population studies. Since a male’s Xchromosome is transmitted only to his female offspring,XSTRs are helpful in some deficient and complex kinship tests such as paternity cases when the disputed child is female, maternity testing and cases where parents are not available but some relatives are [1–5]. An advantage of XSTRs is that in trios involving daughter, the mean exclusion

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Int J Legal Med (2012) 126:327–330

chance (MEC) proposed by Desmarais et al. [6] is higher than forautosomal loci with similar polymorphism information content (PIC) [3, 7–10]. Most studies of X-STRs have been conducted with Asian and European populations, while there are just a few with African and Latin American populations. Therefore, the aim of this study was to develop two multiplex PCR systems to investigate a population in the south of Brazil with an overall of 14 X-STRs markers,...