Search

Mosquitoes occur almost worldwide, and females of some species feed on blood from humans and other animals to support ovum maturation. In warm and hot seasons, such as the summer in Japan, fed mosquitoes are often observed at crime scenes. The current study attempted to estimate the time that elapsed since feeding from the degree of human DNA digestion in mosquito blood meals and also to identify the individual human sources of the DNA using genotyping in two species of mosquito: Culex pipiens pallens and Aedes albopictus. After stereomicroscopic observation, the extracted DNA samples were quantified using a human DNA quantification and quality control kit and were genotyped for 15 short tandem repeats using a commercial multiplexing kit. It took about 3 days for the complete digestion of a blood meal, and genotyping was possible until 2 days post-feeding. The relative peak heights of the 15 STRs and DNA concentrations were useful for estimating the post-feeding time to approximately half a day between 0 and 2 days. Furthermore, the quantitative ratios derived from STR peak heights and the quality control kit (Q129/Q41, Q305/Q41, and Q305/Q129) were reasonably effective for estimating the approximate post-feeding time after 2–3 days. We suggest that this study may be very useful for estimating the time since a mosquito fed from blood meal DNA, although further refinements are necessary to estimate the times more accurately. [ABSTRACT FROM AUTHOR]

A novel method for sex determination, based on the detection of the number of X chromosomes, was established. Current methods, based on the detection of the Y chromosome, can directly identify an unknown sample as male, but female gender is determined indirectly, by not detecting the Y chromosome. Thus, a direct determination of female gender is important because the quality (e.g., fragmentation and amelogenin-Y null allele) of the Y chromosome DNA may lead to a false result. Thus, we developed a novel sex determination method by analyzing the number of X chromosomes using a copy number variation (CNV) detection technique (the comparative Ct method). In this study, we designed a primer set using the amelogenin-X gene without the CNV region as the target to determine the X chromosome copy number, to exclude the influence of the CNV region from the comparative Ct value. The number of X chromosomes was determined statistically using the CopyCaller software with real-time PCR. All DNA samples from participants (20 males, 20 females) were evaluated correctly using this method with 1-ng template DNA. A minimum of 0.2-ng template DNA was found to be necessary for accurate sex determination with this method. When using ultraviolet-irradiated template DNA, as mock forensic samples, the sex of the samples could not be determined by short tandem repeat (STR) analysis but was correctly determined using our method. Thus, we successfully developed a method of sex determination based on the number of X chromosomes. Our novel method will be useful in forensic practice for sex determination. [ABSTRACT FROM AUTHOR]

The results of forensic tests, such as semen identification and short tandem repeat (STR) analysis of extremely aged seminal stains from unsolved sex crimes can provide important evidence. In this study we evaluated whether current forensic methods could be applied to seminal stains that were stored at room temperature for 33-56years (n=2, 33years old; n=1, 41years old; n=1, 44years old; n=1, 56years old). The prostatic acid phosphatase (SM-test reagent), microscopic (Baecchi stain method) and semenogelin (RSID™ Semen Laboratory Kit) tests were performed as discriminative tests for semen. In addition, the mRNA levels of the semen-specific proteins semenogelin 1 (SEMG1) and protamine 2 (PRM2) were investigated. STRs were analyzed using the AmpFlSTR® Identifiler™ PCR Amplification Kit. All samples were positive in the prostatic acid phosphatase and semenogelin tests, and sperm heads were identified in all samples. The staining degree of the aged sperm heads was similar to that of fresh sperm. Although SEMG1 mRNA was not detected in any sample, PRM2 mRNA was detected in three samples. In the STR analysis, all loci were detected in the 33-years-old sample and five loci were detected in the 56-years-old sample. We confirmed that current forensic examinations - including STR analysis - could be applied to extremely aged seminal stains. These results could be useful for forensic practice. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recently, a more accurate and reliable screening test has been investigated for noninvasive prenatal fetal RHD genotyping from D– women. The objective of this study was to perform the new method of noninvasive fetal RHD genotyping with maternal plasma from D– women by use of capillary electrophoresis. STUDY DESIGN AND METHODS: Blood samples were obtained from 8 D+ and 8 D– nonpregnant donors and mixed to make test plasma samples. DNA was extracted and the appropriate conditions relating to the initial sample volume as well as polymerase chain reaction cycle numbers were analyzed to detect the RHD gene with RHD exon 10 primer. Blood samples were also obtained from 13 D– pregnant women ranging from the 12th to 39th weeks of gestation. The presence of the RHD gene and Y-chromosome–specific STR (Y-STR) derived from the fetus was analyzed. The results were compared with the D status of newborns. RESULTS: In samples from 12 D– pregnant women, the RHD gene was detected. In one sample, the RHD gene was not detected but Y-STR loci were demonstrated in this sample, indicating a D– male baby. The results of fetal genotyping were all in concordance with the postpartum samples by serologic tests on D as well as with the sex of newborns. CONCLUSION: Capillary electrophoresis can be used for the determination of fetal RHD status in D– women. This diagnostic method is useful for the noninvasive prenatal diagnosis of the fetal RHD genotyping from D– women. [ABSTRACT FROM AUTHOR]

Fifteen short tandem repeat (STR) loci D3S1358, TH01, D21S11, D18S51, Penta E, D5S818, D13S317, D7S820, D16S539, CSF1PO, Penta D, vWA, D8S1179, TPOX and FGA were analyzed in 164 unrelated Japanese using the PowerPlex® 16 System kit. The genotype frequency distribution of each locus did not deviate from the Hardy–Weinberg equilibrium. Penta E was the best STR for forensic purpose. The combined power of discrimination (PD) was 0.999999999999999978. [Copyright &y& Elsevier]

Abstract: We studied eight X-STRs (DXS7132, DXS7423, DXS8378, DXS10074, DXS10101, DXS10134, DXS10135, HPRTB) polymorphism in 494 unrelated Japanese individuals (313 males, 181 females) using Mentype Argus X-8 PCR Amplification Kit. PD of the eight X-STRs ranged from 0.558 (male) to 0.987 (female). Allele frequencies, number of alleles, and PIC were 0.001–0.587, 6–20, and 0.470–0.913, respectively. [Copyright &y& Elsevier]

• The luminol test was suitable as a preliminary bloodstain test. • DNA and RNA were extracted from all washed bloodstains. • HBB and 18S rRNA were suitable for tests of mRNA detection. • STR typing was successfully performed for all bloodstains with no problems. We investigated whether bloodstain examination and DNA typing can be performed on washed bloodstains on clothes. Blood was dropped onto T-shirts made from 100% cotton or 100% polyester. After drying, the T-shirts were hand-washed with handwashing soap, dishwashing detergent, laundry detergent, soap, or just water until the bloodstains could not be seen. After drying the T-shirts, DNA and RNA were extracted simultaneously from the bloodstained areas using commercial kits. RNA was reverse-transcribed to DNA, and then the detection of the mRNAs for HBB , ACTB , and 18S rRNA was examined. DNA was quantified via real-time PCR, and then STR typing was performed with a commercial kit. The luminol and leucomalachite green tests were used as preliminary bloodstain tests, and an immuno-chromatography kit was used to identify human bloodstains. DNA could be extracted from all washed bloodstains, but more DNA was extracted from cotton T-shirts than from polyester T-shirts. STR typing was successful for all bloodstains without issues such as PCR inhibition. In the human bloodstain identification test using mRNA, almost all bloodstains produced a Ct value for HBB and all bloodstains produced a Ct value for 18S rRNA , whereas few bloodstains produced a Ct value for ACTB. All bloodstains reacted positively to luminol, but some were negative for leucomalachite green. Most of the bloodstains did not react positively in the human bloodstain identification test using the immuno-chromatography kit. The results suggest that human bloodstain identification and DNA typing can still be performed after clothes with bloodstains are washed. [ABSTRACT FROM AUTHOR]