MiniY-STR quadruplex systems with short amplicon lengths for analysis of degraded DNA samples

Fetal male lineage determination by analysis of Y-chromosome STR haplotype in maternal plasma

The aim of this study is to determine the fetus Y-STR haplotype in maternal plasma during pregnancy and estimate, non-invasively, if the alleged father and fetus belong to the same male lineage. The study enrolled couples with singleton pregnancies and known paternity. All participants signed informed consent and the local ethics committee approved the study. Peripheral blood was collected in EDTA tubes (mother) and in FTA paper (father). Maternal plasma DNA was extracted by using NucliSens EasyMAG. Fetal gender was determined by qPCR targeting DYS-14 in maternal plasma and it was also confirmed after the delivery. From all included volunteers, the first consecutive 20 mothers bearing male fetuses and 10 mothers bearing female fetuses were selected for the Y-STR analysis. The median gestational age was 12 weeks (range 12-36). All DNA samples were subjected to PCR amplification by PowerPlex Y23, ampFLSTR Yfiler, and two in-house multiplexes, which together accounts for 27 different Y-STR. The PCR products were detected with 3500 Genetic Analyzer and they were analyzed using GeneMapper-IDX. Fetuses' haplotypes (Yfiler format) were compared to other 5328 Brazilian haplotypes available on Y-chromosome haplotypes reference database (YHRD). As a result, between 22 and 27 loci were successfully amplified from maternal plasma in all 20 cases of male fetuses. None of the women bearing female fetuses had a falsely amplified Y-STR haplotype. The haplotype detected in maternal plasma completely matched the alleged father haplotype in 16 out of the 20 cases. Four cases showed single mismatches and they did not configure exclusions; 1 case showed a mutation in the DYS 458 locus due to the loss of one repeat unit and 3 cases showed one DYS 385I/II locus dropout. All mismatches were confirmed after the delivery. Seventeen fetuses' haplotypes were not found in YHRD and one of them had a mutation, which corresponded to the paternity probability of 99.9812% and 95.7028%, respectively. Three fetuses' haplotypes occurred twice in YHRD, which corresponded to paternity probability of 99.9437%. In conclusion, high discriminatory fetal Y-STR haplotype could be determined from maternal plasma during pregnancy starting at 12 weeks of gestation. All male fetuses could be attributed to the alleged father male lineage early in pregnancy. The high probability of paternity associated with each case suggests that the relationship is not random and this strategy can be use as an alternative for male fetal kinship analysis.

Capillary electrophoresis of human mtDNA control region sequences from highly degraded samples using short mtDNA amplicons

The forensic applications of mtDNA sequencing center primarily on samples that are either highly degraded or contain little or no nuclear DNA, since the testing of these sample types is often unsuccessful with more widely used nuclear STR profiling assays. In these cases, sequence data from the noncoding mtDNA control region are targeted due to its high variability. However, the ease of authentic DNA recovery and the strategy used for recovery depend strictly on the quality of the sample. In this chapter, we will cover mitochondrial DNA sequencing procedures for short mtDNA amplicons which range in size from 100 to 350 bp. Generally speaking, amplicons of this size are required only for the most degraded specimens, and the protocols described here have been specifically developed for recalcitrant human skeletal remains encountered during the course of a large-scale missing persons' identification effort. DNA templates from these types of specimens tend to exhibit various forms of intrastrand damage that, in turn, manifest as artifacts in the sequence data. Because these artifacts are not generally observed among sequence data from pristine templates, we address the particular data idiosyncrasies that warrant additional scrutiny. Although this chapter will primarily highlight this particular application, the basic experimental parameters and data considerations should easily extend to other applications and/or sample types. The protocols described here have been deliberately designed to produce raw sequence electropherograms and final mtDNA profiles that adhere to the strictest forensic guidelines in terms of overall data quality.

Sample stacking capillary electrophoretic microdevice for highly sensitive mini Y short tandem repeat genotyping

Lab-on-a-chip provides an ideal platform for short tandem repeat (STR) genotyping due to its intrinsic low sample consumption, rapid analysis, and high-throughput capability. One of the challenges, however, in the forensic human identification on the microdevice is the detection sensitivity derived from the nanoliter volume sample handling. To overcome such a sensitivity issue, here we developed a sample stacking CE microdevice for mini Y STR genotyping. The mini Y STR includes redesigned primer sequences to generate smaller-sized PCR amplicons to enhance the PCR efficiency and the success rate for a low copy number and degraded DNA. The mini Y STR amplicons occupied in the 5- and 10-mm stacking microchannels are preconcentrated efficiently in a defined narrow region through the optimized sample stacking CE scheme, resulting in more than tenfold improved fluorescence peak intensities compared with that of a conventional cross-injection microcapillary electrophoresis method. Such signal enhancement allows us to successfully analyze the Y STR typing with only 25 pg of male genomic DNA, with high background of female genomic DNA, and with highly degraded male genomic DNA. The combination of the mini Y STR system with the novel sample stacking CE microdevice provides the highly sensitive Y STR typing on a chip, making it promising to perform high-performance on-site forensic human identification.

Haplotypes of six miniY-STR loci in the Han population from Sichuan province and the Zhuang population in Guangxi Zhuang autonomous region

Human Y-chromosomal short tandem repeat (miniY-STR) with short amplicon lengths is useful in forensic applications, especially in the analysis of degraded DNA samples. The present study aims to investigate the population database of six miniY-STR (DYS570, DYS556, DYS576, DYS522, DYS508, DYS540). 307 blood samples were taken from the Han population, and 253 samples were taken from the Zhuang population. The amplification product lengths detected ranged from 95 to 170 bp. A total of 395 haplotypes, 303 of them unique, were found. The haplotype diversity of the Han was 0.9980 and of the Zhuang 0.9965, indicating a high discriminating power of these six miniY-STR loci in these two populations.

Population genetics and mutational events at 6 Y-STRs in Korean population

Haplotype frequencies for 6 Y-STRs (DYS522, DYS533, DYS549, DYS570, DYS576 and DYS643) were determined in 539 unrelated Korean males. A total of 375 haplotypes were observed with the overall haplotype diversity of 0.9967. In DYS570, we found new point-3 microvariant allele series, i.e., 18.3, 19.3 and 20.3. DNA sequence analysis showed that the full repeat sequences were [TTTC](n)ttc[TTTC](5). Duplicated DYS643 allele was found and discussed on its forensic impact on the Y-STR interpretation of male-male mixtures. In 140 confirmed father/son pairs, one mutation was found in DYS576 with the overall mutation rate of 1.10x10(-3)/locus/generation (95% CI 0.31-1.89x10(-3)).

Identification of forensically relevant body fluids using a panel of differentially expressed microRNAs

The serology-based methods routinely used in forensic casework for the identification of biological fluids are costly in terms of time and sample and have varying degrees of sensitivity and specificity. Recently, the use of a molecular genetics-based approach using messenger RNA (mRNA) profiling has been proposed to supplant conventional methods for body fluid identification. However, the size of the amplification products used in these mRNA assays (approximately 200-300 nt) might not be ideal for use with degraded or compromised samples frequently encountered in forensic casework. Recently, there has been an explosion of interest in a novel class of small noncoding RNAs, microRNAs (miRNAs, approximately 20-25 bases in length), with numerous published studies reporting that some miRNAs are expressed in a tissue-specific manner. In this article, we provide the first comprehensive evaluation of miRNA expression in dried, forensically relevant biological fluids--blood, semen, saliva, vaginal secretions, and menstrual blood--in an attempt to identify putative body fluid-specific miRNAs. Most of the 452 human miRNAs tested (approximately 67% of the known miRNAome) were either expressed in multiple body fluids or not expressed at all. Nevertheless, we have identified a panel of nine miRNAs--miR451, miR16, miR135b, miR10b, miR658, miR205, miR124a, miR372, and miR412--that are differentially expressed to such a degree as to permit the identification of the body fluid origin of forensic biological stains using as little as 50 pg of total RNA. The miRNA-based body fluid identification assays were highly specific because the miRNA expression profile for each body fluid was different from that obtained from 21 human tissues. The results of this study provide an initial indication that miRNA profiling may provide a promising alternative approach to body fluid identification for forensic casework.

Evaluation of miniY-STR multiplex PCR systems for extended 16 Y-STR loci

We developed three short amplicon Y-chromosomal short tandem repeat (miniY-STR) polymerase chain reaction multiplex systems for 16 Y-STR loci (DYS441, DYS446, DYS462, DYS481, DYS485, DYS495, DYS505, DYS510, DYS511, DYS549, DYS 575, DYS578, DYS593, DYS618, DYS638, and DYS643), using newly designed primer sets. In an assay of 238 Japanese males using the three miniY-STR systems, amplification product lengths ranged from 91 to 151 bp for all 16 Y-STR loci. We identified 212 different haplotypes among the 238 individuals, finding haplotype diversity and discrimination capacity of 0.9974 and 0.8908, respectively. An assay of degraded DNA samples using the three miniY-STR multiplex systems, including artificially degraded samples and degraded forensic casework samples, proved remarkably effective. In conclusion, analyses of miniY-STR multiplex systems will play an important role in forensic applications involving degraded DNA samples for which genotyping using only commercial kits is ill-suited.

MiniSTR multiplex systems based on non-CODIS loci for analysis of degraded DNA samples

We describe two short amplicon autosomal short tandem repeat (miniSTR) quadruplex systems for eight loci D1S1171, D2S1242, D3S1545, D4S2366, D12S391, D16S3253, D20S161, and D21S1437, unlinked from the combined DNA index system (non-CODIS) loci, using newly designed primer sets. The results of an assay of 411 Japanese individuals showed that polymerase chain reaction (PCR) products within the eight loci were less than 150bp in size, without the seven additional bases for adenylation. The frequency distributions in the loci showed no deviations from Hardy-Weinberg equilibrium expectations. The accumulated power of discrimination and power of exclusion for the eight loci were 0.9999999991 and 0.998, respectively. For assay of highly degraded DNA, including artificially degraded samples and the degraded forensic casework samples assessed with the present miniSTR quadruplex systems, the systems proved quite effective in analyzing degraded DNA.