Molecular characterization of a null allele at locus DXS8378

Typing of X-chromosomal short tandem repeat (STR) loci in a deficiency paternity case revealed a single Mendelian incompatibility between a female child and her putative grandmother, consisting of an opposite homozygosity at locus DXS8378. The presence of a null allele due to a primer binding site mutation on the child's paternally inherited X chromosome was confirmed by amplification with newly designed DXS8378 external primers. Sequencing analysis showed a point mutation (C > T transition at position 168, according to GenBank accession G08098) in the binding site of the original DXS8378 reverse primer.     

Interrogation of short tandem repeats using fluorescent probes and melting curve analysis: A step towards rapid DNA identity screening

Current forensic DNA profiling methods rely on the analysis of samples at specialised laboratories with an average turnaround time of several days. The ability to rapidly determine a partial profile of short tandem repeats at the point-of-arrest would be of great benefit to police forces around the world, for example enabling a suspect to be rapidly included or excluded from an investigation. We have developed a homogeneous PCR method for the interrogation of STR loci utilising fluorescent oligonucleotide probes and melting curve analysis. Alleles of the D18S51, TH01 and D8S1179 loci were differentiated and identified on the basis of target length and probe melting temperature. Assay performance was evaluated by comparing melting peak data with the AmpFlSTR^® SGM Plus^® system. The method is compatible with direct analysis of unpurified buccal swab samples, enabling a partial STR profile to be generated within 1 h.     

The Distribution of Household Property Crimes

Previous studies have established that repeat victimizations occur more frequently than would be expected if households within a particular area were victimized randomly. This implies that characteristics of the household affect the victimization rate. Even controlling for these characteristics, we find that a Poisson model does not capture the distribution of victimizations because repeat victimizations are more concentrated than it would indicate. This leads us to adopt the negative binomial generalization of the Poisson model. Our analysis uses sociodemographic attributes of the household and community-level characteristics to predict victimizations, with the victimization data being the observed number of property crime victimizations from the 1992 British Crime Survey. The negative binomial generalization is found to be highly statistically significant and the crime concentration it implies becomes much more marked as the predicted number of victimizations increases.     

Polymorphism of eight X-chromosomal STRs in a Japanese population

Eight X-chromosomal short tandem repeat (X-STR) markers were analyzed in 258 unrelated Japanese (144 males and 114 females) using Mentype^® Argus X-8 PCR Amplification Kit (Biotype AG) which contains DXS7132, DXS7423, DXS8378, DXS10074, DXS10101, DXS10134, DXS10135 and HPRTB. The DXS10135 locus proved to be highly polymorphic marker (PIC: 0.945) and the DXS7423 showed the lowest value (PIC: 0.453). The exact test for genotype distribution showed no significant deviation from the Hardy-Weinberg equilibrium.     

Population data of eight X-chromosomal STR markers in Ewe individuals from Ghana

The investigation of the X-linked DNA markers are well established in the forensic routine case work. We studied an Ewe population sample from Ghana. The eight X-chromosomal STRs DXS10135, DXS8378, DXS7132, DXS10074, HPRTB, DXS10101, DXS10134 and DXS7423 were analyzed in 182 Ewe individuals (108 females and 74 males) from the region of Sogakofe (Ghana). Allele frequencies and statistical parameter as well as comparison with known data from Germans and with data from an Amharic population (Ethiopia) are presented.     

Post-injection hybridization of complementary DNA strands on capillary electrophoresis platforms: A novel solution for dsDNA artifacts

Several laboratories have reported the occurrence of a split or n − 1 peak at the vWA locus in PowerPlex^® 16 and PowerPlex^® ES amplification products separated on 4- and 16-capillary electrophoresis instruments. The root cause of this artifact is post-PCR reannealing of the unlabeled, unincorporated vWA primer to the 3′-end of the tetramethylrhodamine (TMR)-labeled strand of the vWA amplicon. This reannealing occurs in the capillary post-electrokinetic injection. The split peak is eliminated by incorporation into the loading cocktail of a sacrificial hybridization sequence (SHS) oligonucleotide that is complementary to the vWA primer. The SHS preferentially anneals to the primer instead of the TMR-labeled strand of the vWA amplicon. In addition, the n − 10/n − 18 artifact that may be seen at the vWA locus was determined to be due to double-stranded amplicon formed post-electrokinetic injection into the capillary. This was also eliminated by adding in two Complementary Oligo Targets (COT1 and COT2) in addition to the SHS oligonucleotide into the loading cocktail. These three oligonucleotides are complementary to the 33 bases at the 5′-end of the unlabeled vWA amplicon strand and the 60 bases at its 3′-end and therefore compete for hybridization to the TMR-labeled amplicon strand. Incorporation of these three oligonucleotides in the Internal Lane Standard 600 (ILS600) eliminate both the split peak and n − 10/n − 18 artifact in PowerPlex^® 16 and PowerPlex^® ES amplification products without affecting sizing of alleles at the vWA locus or any locus in the PowerPlex^® 16, PowerPlex^® Y, PowerPlex^® ES, AmpFlSTR^® Profiler Plus^® ID, AmpFlSTR^® Cofiler^®, and AmpFlSTR^® SGM Plus^® kits.     

An ambiguous sequence-based allele of SE33

SE33 was a well-known autosomal short tandem repeat (STR) marker that was high polymorphic and therefore was high discrimination power. The sequence structure of STR markers has been increasingly explored with next-generation sequencing (NGS) technology. The sequencing resulted in the development of a new locus designation and allele nomenclature that was also backward compatible with the conventional capillary electrophoresis. SE33 was one of the STR markers that had been coamplified by Forenseq™ Signature Prep Kit (Verogen) but were not analyzed and illustrated in the Universal Analysis Software (UAS) (Verogen). This study reported an ambiguous sequence-based allele 16.3 of the SE33 locus. This allele was observed while analyzed by STRait Razor 3.0. The configuration file was modified from the previous studies to include 15 bp of 5′ flanking region and 24 bp of 3′ flanking region. The ambiguous allele was called 16.3 (106 bp) with a read count of 2070. However, the sequence of the repeat region cannot be designated as allele 16.3. Several possible scenarios for allele designation were presented and discussed.     

胎教与小说之关系探源

在古代,胎教与小说有着密切的关系.探究胎教与小说关系之源将有利于妇女优生优育的研究,有利于小说观念历史演变的研究,尤其是有利于弘扬中国优秀的传统文化.     

用串联质谱法提高毒鼠强的检测灵敏度

目的建立一种能避免生物样品中杂质的干扰,提高毒鼠强检测灵敏度的方法。方法应用串联质谱法,对生物样品中的毒鼠强进行检验研究。结果在样品无需净化的情况下,以m/z240为母离子,当激活电压在0.8V左右时,毒鼠强二次电离的离子碎片适中,质谱谱图清晰;此时进样量为1.0ng的毒鼠强,其信噪比(s/n)为87,经与全扫描质谱法进行比较灵敏度大为提高。结论该方法能有效提高毒鼠强检测灵敏度,适用于同类案件检验。     

D18S872基因座在汉、维、蒙古、回族群体中的遗传多态性研究及其应用

目的　调查D18S872基因座在成都汉族 ,新疆维族和蒙古族 ,甘肃回族 4个民族中的遗传多态性 ,获得群体遗传学基本数据。　方法　等位基因分型标准物制备采用分子克隆技术 ,样本基因分型采用PCR和PAG垂直电泳技术、银染显色方法。　结果　获得D18S872基因座等位基因分型标准物及该基因座在 4个群体中的遗传学数据。　结论　结果表明D18S872基因座在法医学个人识别和亲子鉴定中有一定的应用价值。