Balazs Egyed

Canine STR analyses in forensic practice. Observation of a possible mutation in a dog hair.

Abstract. In a case of the death of a 7-year-old boy, the police investigations revealed a possible dog attack contrary to the witness testimonies. DNA investigations were carried out from hairs, saliva and bloodstains with 10 canine-specific STR loci by the use of fluorescently labelled multiplex PCR and the ABI PRISM 310 genetic analyzer. The analysis of one hair sample revealed one allele deviation from the profile of the putative Rottweiler perpetrator possibly caused by a mutation. The PCR fragments in question at the PEZ20 locus were sequenced and compared with the alleles detected in the Hungarian canine population and identified on a repeat number basis. The allele frequencies were determined based on typing of 242 genetically independent canine individuals from 72 breeds. The results suggested that two of the canine individuals could be the perpetrators.

Hungarian mtDNA population databases from Budapest and the Baranya county Roma

To facilitate forensic mtDNA testing in Hungary, we have generated control region databases for two Hungarian populations: 211 individuals were sampled from the urban Budapest population and 208 individuals were sampled from a Romani (“gypsy”) population in Baranya county. Sequences were generated using a highly redundant approach to minimize potential database errors. The Budapest population had high sequence diversity with 180 lineages, 183 polymorphic positions, and a random match probability of 1%. In contrast, the Romani population exhibited low sequence diversity, with only 56 lineages, 109 segregating sites, and a random match probability of 8.8%. The mtDNA haplogroup compositions of the two populations were also distinct, with the large proportion of haplogroup M samples (35%) in the Roma the most obvious difference between the two populations. These factors highlight the importance of considering population structure when generating reference databases for forensic testing purposes. Comparisons between our Romani population sample and other published data indicate the need for heightened caution when sampling and using mtDNA databases of small endogamous populations. The Romani populations that we compared showed significant departures from genetic uniformity.

Canine microsatellite polymorphisms as the resolution of an illegal animal death case in a Hungarian Zoological Gardens

Abstract Several animal carcasses were found in the paddocks of a Hungarian County Zoo during 1 week. The ¶14 animals killed were thought to be the victims of a dogfight training. The primary suspect was the security guard of the Zoo with his guard dogs. DNA tests were carried out on hairs and bloodstains and 10 canine-specific STR loci were analysed by fluorescently labelled multiplex PCR using the ABI PRISM 310 Genetic Analyzer. The results confirmed that the killer was a single animal and all of the guard dogs were excluded.

Variations in primer sequences are the origin of allele drop-out at loci D13S317 and CD4

Abstract STRs have become almost the exclusive tool of genetic scientists in forensic typing work. Consequently, large numbers of samples are genotyped and the detection of rare abnormalities is to be expected. We found rare losses of alleles, also known as drop-out, at the two STR loci D13S317 and CD4. Drop-out at D13S317 was accidentally found in typing of suspects in a murder case and three other examples of drop-out were found at locus CD4 during paternity testing. The lost alleles reappeared when alternative PCR primer pairs were used. Sequences of lost alleles were characterised at the molecular level after cloning. Variations were found in the primer sequences and these are believed to prevent amplification or to reduce amplification yield and to be the origin of the allele drop-out.

Migration Rates and Genetic Structure of two Hungarian Ethnic Groups in Transylvania, Romania

Transylvanias ethnic mosaic is composed of Romanians, German Saxons and Hungarians. The ethnic groups of the Hungarian minority that settled in Romania show differences in dialects, customs and religious affiliations. In this study entire mtDNA control region sequences from 360 individuals of Hungarian ethnicity from two populations (the Csángó and the Székely), settled in the historical region of Transylvania in Romania, were generated and analyzed following high quality sequencing standards. Phylogenetic analyses were used for haplogroup determination, quasi‐median network analyses were applied for the visualization of character conflicts, and median joining reconstructions were used for depicting haplotype structures. Affiliation of haplotypes to major west Eurasian haplogroups was confirmed using coding region SNPs. Gene flow between the two populations was low and biased towards a higher migration rate from the Csángó to the Székely than vice versa. Phylogeographic analyses revealed effects of genetic isolation within the Csángó population, which is, in its genetic structure, clearly different from the Székely population. The pronounced genetic divergence between the two populations is in sharp contrast to the expectation of high genetic similarity due to the close geographic proximity of their native homelands. The population data will be incorporated in the EMPOP database (http://www.empop.org).

Mitochondrial control region sequence variations in the Hungarian population: Analysis of population samples from Hungary and from Transylvania (Romania)

To assess the mitochondrial DNA polymorphisms of the Hungarian population in the Carpathian basin and to facilitate forensic mtDNA testing a collection of control region sequences were generated from two population samples from Hungary and from two Hungarian speaking populations from Transylvania (Romania). Entire control region sequencing was performed by an automated laboratory process and data export without any manual transcription. The random match probability and pairwise comparisons within and between the datasets is reported. This study highlights the importance of considering population structure when generating reference databases for forensic testing. Comparisons between our population samples indicate the need for heightened caution when sampling, and using mtDNA databases of small endogamous populations. The population data will be incorporated in the EMPOP database (www.empop.org).

Analysis of eight STR loci in two Hungarian populations.

Abstract A multiplex reaction for the eight STR loci D3S1358, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 was used to generate allele frequency databases for two Hungarian population samples, Caucasians from the Budapest area and Romanies from Baranya county. During the analysis two intermediate-sized alleles and a sequence variant allele were observed at the D7S820 locus. All three types of allelic variants were found to have modifications in the same block of a (T)9 stretch located within the 3′ flanking region of each allele, which may indicate a possible higher mutation rate of this (T)9 block. For the loci D3S1358 and D7S820 the Romany population database showed departures from Hardy-Weinberg equilibrium. The forensic efficiency values for the Romany population were slightly different from those found in the Hungarian Caucasian population. Comparing the allele frequency values by G-statistic, calculating the FST indices and with the pair-wise comparisons of inter-population variance, the two Hungarian populations could be distinguished using data from the eight STR loci.

Inter-laboratory evaluation of the EUROFORGEN Global ancestry-informative SNP panel by massively parallel sequencing using the Ion PGM™.

The EUROFORGEN Global ancestry-informative SNP (AIM-SNPs) panel is a forensic multiplex of 128 markers designed to differentiate an individuals ancestry from amongst the five continental population groups of Africa, Europe, East Asia, Native America, and Oceania. A custom multiplex of AmpliSeq™ PCR primers was designed for the Global AIM-SNPs to perform massively parallel sequencing using the Ion PGM™ system. This study assessed individual SNP genotyping precision using the Ion PGM™, the forensic sensitivity of the multiplex using dilution series, degraded DNA plus simple mixtures, and the ancestry differentiation power of the final panel design, which required substitution of three original ancestry-informative SNPs with alternatives. Fourteen populations that had not been previously analyzed were genotyped using the custom multiplex and these studies allowed assessment of genotyping performance by comparison of data across five laboratories. Results indicate a low level of genotyping error can still occur from sequence misalignment caused by homopolymeric tracts close to the target SNP, despite careful scrutiny of candidate SNPs at the design stage. Such sequence misalignment required the exclusion of component SNP rs2080161 from the Global AIM-SNPs panel. However, the overall genotyping precision and sensitivity of this custom multiplex indicates the Ion PGM™ assay for the Global AIM-SNPs is highly suitable for forensic ancestry analysis with massively parallel sequencing.

Forensic interlaboratory evaluation of the ForFLUID kit for vaginal fluids identification

Identification of vaginal fluids is an important step in the process of sexual assaults confirmation. Advances in both microbiology and molecular biology defined technical approaches allowing the discrimination of body fluids. These protocols are based on the identification of specific bacterial communities by microfloraDNA (mfDNA) amplification. A multiplex real time-PCR assay (ForFLUID kit) has been developed for identifying biological fluids and for discrimination among vaginal, oral and fecal samples. In order to test its efficacy and reliability of the assay in the identification of vaginal fluids, an interlaboratory evaluation has been performed on homogeneous vaginal swabs. All the involved laboratories were able to correctly recognize all the vaginal swabs, and no false positives were identified when the assay was applied on non-vaginal samples. The assay represents an useful molecular tool that can be easily adopted by forensic geneticists involved in vaginal fluid identification.

Mapping human dispersals into the Horn of Africa from Arabian Ice Age refugia using mitogenomes

Rare mitochondrial lineages with relict distributions can sometimes be disproportionately informative about deep events in human prehistory. We have studied one such lineage, haplogroup R0a, which uniquely is most frequent in Arabia and the Horn of Africa, but is distributed much more widely, from Europe to India. We conclude that: (1) the lineage ancestral to R0a is more ancient than previously thought, with a relict distribution across the Mediterranean/Southwest Asia; (2) R0a has a much deeper presence in Arabia than previously thought, highlighting the role of at least one Pleistocene glacial refugium, perhaps on the Red Sea plains; (3) the main episode of dispersal into Eastern Africa, at least concerning maternal lineages, was at the end of the Late Glacial, due to major expansions from one or more refugia in Arabia; (4) there was likely a minor Late Glacial/early postglacial dispersal from Arabia through the Levant and into Europe, possibly alongside other lineages from a Levantine refugium; and (5) the presence of R0a in Southwest Arabia in the Holocene at the nexus of a trading network that developed after ~3 ka between Africa and the Indian Ocean led to some gene flow even further afield, into Iran, Pakistan and India.