13个STR基因座在亲子鉴定案例中的基因突变观察

目的 观察美国 CODIS系统的 13个 STR基因座在532例认定亲子关系的亲子鉴定案中的基因突变情况,探讨STR基因座突变率及突变类型。方法 经“Profiler Plus”及“Cofiler”试剂盒检测的587例亲子鉴定案,对其中有1～2个STR基因座不符合遗传规律者,增加HLA等血型基因和“PowerPlex16~(TM)”试剂盒检测。必要时,还增加Y-STR基因座检测和HLA等位基因测序。结果 认定亲子关系的532例,观察1052次减数分裂,发现17例亲子鉴定中的18次基因突变事件,其中16例1个STR基因座的基因发生突变,1例2个STR基因座的基因发生突变;突变的基因座包括D5S818、D3S1358、D16S539、CSFIPO、D21S11、D13S317、D7S820、vWA、D18S51和FGA,其中以FGA和D18S51基因座的突变率最高(0.29％);18次突变事件,其中来自父亲11次,来自母亲5次,无法确定2次。结论 用美国CODIS系统的STR基因座进行亲子鉴定,在有1～2个基因座不符合遗传规律时,要综合分析,并增加其它的遗传标记进行检测。     

New autosomal STR loci

Additional STR loci can be beneficial for a number of human identity, forensic casework, and DNA database applications. The marker selection and characterization process applied at NIST in developing these new loci and assays are described along with concordance testing results from non-overlapping PCR primers. A 23plex for simultaneous amplification of 22 autosomal STR loci and an amelogenin sex-typing assay is also demonstrated.     

Forensic typing of autosomal SNPs with a 29 SNP-multiplex—Results of a collaborative EDNAP exercise

We report the results of an inter-laboratory exercise on typing of autosomal single nucleotide polymorphisms (SNP) for forensic genetic investigations in crime cases. The European DNA Profiling Group (EDNAP), a working group under the International Society for Forensic Genetics (ISFG), organised the exercise. A total of 11 European and one US forensic genetic laboratories tested a subset of a 52 SNP-multiplex PCR kit developed by the SNPforID consortium. The 52 SNP-multiplex kit amplifies 52 DNA fragments with 52 autosomal SNP loci in one multiplex PCR. The 52 SNPs are detected in two separate single base extension (SBE) multiplex reactions with 29 and 23 SNPs, respectively, using SNaPshot kit, capillary electrophoresis and multicolour fluorescence detection. For practical reasons, only the 29 SBE multiplex reaction was carried out by the participating laboratories. A total of 11 bloodstains on FTA cards including a sample of poor quality and a negative control were sent to the laboratories together with the essential reagents for the initial multiplex PCR and the multiplex SBE reaction. The total SNP locus dropout rate was 2.8% and more than 50% of the dropouts were observed with the poor quality sample. The overall rate of discrepant SNP allele assignments was 2.0%. Two laboratories reported 60% of all the discrepancies. Two laboratories reported all 29 SNP alleles in all 10 positive samples correctly. The results of the collaborative exercise were surprisingly good and demonstrate that SNP typing with SBE, capillary electrophoresis and multicolour detection methods can be developed for forensic genetics.     

Case report: Identification of skeletal remains using short-amplicon marker analysis of severely degraded DNA extracted from a decomposed and charred femur

Applying two extraction protocols to isolate DNA from a charred femur recovered after a major forest fire, a range of established and recently developed forensic marker sets that included mini-STRs and SNPs were used to type the sample and confirm identity by comparison to a claimed daughter of the deceased. Identification of the remains suggested that the individual had been dead for 10 years and the DNA was therefore likely to be severely degraded from the combined effects of decomposition and exposure to very high temperatures. We used new marker sets specifically developed to analyze degraded DNA comprising both reduced-length amplicon STR sets and autosomal SNP multiplexes, giving an opportunity to assess the ability of each approach to successfully type highly degraded material from a challenging case. The results also suggest a modified ancient DNA extraction procedure offers improved typing success from degraded skeletal material.     

单细胞凝胶电泳检测大鼠死后肝细胞核DNA降解

目的应用单细胞凝胶电泳技术(SCGE)检测大鼠死后肝细胞核DNA降解规律,分析与死亡时间的关系,为早期死亡时间的推断提供新的方法。方法在大鼠死后30h内,每隔3h取肝组织样本进行单细胞凝胶电泳,用共聚焦显微镜摄取彗星图像,应用彗星图像分析软件(IM I1.0)进行图像分析,并作统计学分析。结果死后大鼠的肝细胞在电泳图像上出现明显的彗星形拖尾,其尾长(TL)、尾矩(TM)在一定的时间范围内(0~18h)随死亡时间的延长而逐渐增大,二者均与死亡时间(PM I)呈现一定的相关回归关系。结论单细胞凝胶电泳技术可应用于早期死亡时间的推断。