法医学二代测序标准化进展与展望

二代测序技术可检测多种法医遗传标记获取海量序列信息,满足法医学实践中精准个体识别、复杂亲缘关系鉴定、特征刻画等应用需求。国内外已开展大量二代测序法医学应用科研工作,但由于缺乏行业标准,二代测序在我国公安实战中并未得到有效应用。目前,法医学二代测序的标准制定面临检测靶标特殊、测序技术流程和结果分析不统一等挑战。本文从核酸标准参考物、测序技术要求、序列多态STR等位基因命名规则等方面,梳理国外法医学二代测序标准化工作进展,并总结国内二代测序检测行业标准现状,希冀为我国法医学二代测序的标准建设提供思路和参考。     

Discrimination between sediment and soil samples for forensic purposes using elemental data: an investigation of particle size effects

This paper reports the results of an investigation to quantify variations in elemental concentrations amongst different particle size fractions obtained from a suite of sediment samples collected from the River Avon, UK. Concentrations of 49 elements determined by inductively coupled plasma spectrometry (ICP-AES and ICP-MS) were compared using conventional and multivariate statistical methods in order to assess compositional differences between different size fractions and between different samples. The results showed significant differences between different size fractions and the bulk sediments, but indicated that all of the size fractions considered (<150, 63-150, 20-63 and <20microm) provided an adequate basis on which to identify associations and differences between samples. It was concluded that, while in certain specific circumstances it may be most appropriate to make forensic comparisons based on a very narrowly defined particle size range, for the majority of purposes the <150microm fraction provides the best compromise between sample size requirements and data resolution.     

Inference structures for crime analysis and intelligence: the example of burglary using forensic science data

There has been much work dedicated to crime analysis and intelligence in recent times. Independently, physical evidence has shown great potential for linking crimes and bringing solid informative data through the increased use of multiple databases. However, their informative potential is still often underestimated and has been poorly integrated into police information systems. We propose a framework that fully introduces this data into an intelligence based system. This framework is built on the study of inference structures extracted from investigators’ every day implicit reasoning processes. Five specific inferences are studied with the particular problem of serial burglary investigation across independent police and legal structures. On the basis of such an analytical approach, a computer prototype has been designed; it has shown great promise and has resulted in several operational successes.     

Routine forensic use of the mitochondrial 12S ribosomal RNA gene for species identification

Since July 2004, Mitotyping Technologies has been amplifying and sequencing a approximately 150 base pair fragment of mitochondrial DNA (mtDNA) that codes for 12S ribosomal RNA, to identify the species origin of nonhuman casework samples. The approximately 100 base pair sequence product is searched at http://www.ncbi.nlm.nih.gov/BLAST and the species match is reported. The use of this assay has halved the number of samples for which no mtDNA results are obtained and is especially useful on hairs and degraded samples. The availability of species determination may aid forensic investigators in opening or closing off lines of inquiry where a highly probative but challenging sample has been collected.