How to avoid driving DNA caseworkers crazy: CaseSolver,an expert system to investigate complex crime scenes

DNA analyses can be used for both investigative (crime scene-focused), or evaluative (suspect-focused) reporting. Investigative, DNA-led exploration of serious crimes always involves the comparison of hundreds of biological samples submitted by the authorities for analysis. Crime stain comparisons include both evidence to evidence profiles and reference to evidence profiles. When many complex DNA results (mixtures, low template LT-DNA samples) are involved in the investigation of a crime, the manual comparison of DNA profiles is very time-consuming and prone to manual errors. In addition, if the person of interest is a minor contributor, the classical approach of performing searches of national DNA databases is problematic because it is realistically restricted to clear major contributors and the occurrence of masking and drop-out means that there will not be a definitive DNA profile to perform the search with.CaseSolver is an open source expert system that automates analysis of complex cases. It does this by three sequential steps: a) simple allele comparison b) likelihood ratio (LR) based on a qualitative model (forensim) c) LR based on a quantitative model (EuroForMix). The software generates a list of potential match candidates, ranked according to the LRs, which can be exported as a report. The software can also identify contributors from small or large databases (e.g., staff database or 1 mill. individuals). In addition, an informative graphical network plot is generated that easily identifies contributors in common to multiple stains. Here we describe recent improvements made to the software in version v1.5.0, made in response to user requirements during intensive casework usage.     

Probabilistic expert systems for handling artifacts in complex DNA mixtures

This paper presents a coherent probabilistic framework for taking account of allelic dropout, stutter bands and silent alleles when interpreting STR DNA profiles from a mixture sample using peak size information arising from a PCR analysis. This information can be exploited for evaluating the evidential strength for a hypothesis that DNA from a particular person is present in the mixture. It extends an earlier Bayesian network approach that ignored such artifacts. We illustrate the use of the extended network on a published casework example.     

Quick Screening of Crystal Methamphetamine/Methyl Sulfone Exhibits by Raman Spectroscopy

Abstract: The analysis of mixtures of “crystal meth” (usually comprised of methyl sulfone [MS] and methamphetamine [MA]) by gas chromatography‐mass spectrometry (GCMS) is routine in many forensic drug laboratories. The utilization of Raman spectroscopy for the identification of such mixtures quickly and without the need for a separation technique is discussed. Samples were dissolved in water and Raman spectra of the resulting aqueous solutions were collected. By comparing these spectra to spectra of methylsulfone and MA mixtures of known composition, an indication of the composition of the sample can be obtained in only a few minutes. This spectral comparison also can be used as a semi‐quantitative analysis of MA concentrations in such exhibits.     

Single source DNA profile recovery from single cells isolated from skin and fabric from touch DNA mixtures in mock physical assaults

The ability to obtain DNA profiles from trace biological evidence is routinely demonstrated with so-called ‘touch DNA evidence’, which is generally perceived to be the result of DNA obtained from shed skin cells transferred from a donor's hands to an object or person during direct physical contact. Current methods for the recovery of trace DNA employ swabs or adhesive tape to sample an area of interest. While of practical utility, such ‘blind-swabbing’ approaches will necessarily co-sample cellular material from the different individuals whose cells are present on the item, even though the individuals' cells are principally located in topographically dispersed, but distinct, locations on the item. Thus the act of swabbing itself artifactually creates some of the DNA mixtures encountered in touch DNA samples. In some instances involving transient contact between an assailant and victim, the victim's DNA may be found in such significant excess as to preclude the detection and typing of the perpetrator's DNA. In order to circumvent the challenges with standard recovery and analysis methods for touch DNA evidence, we reported previously the development of a ‘smart analysis’ single cell recovery and DNA analysis method that results in enhanced genetic analysis of touch DNA evidence. Here we use the smart single cell analysis method to recover probative single source profiles from individual and agglomerated cells from various touched objects and clothing items belonging to known donors. We then use the same approach for the detection of single source male donor DNA in simulated physical contact/assault mixture samples (i.e. male ‘assailant’ grabbing the wrist, neck or clothing from the female ‘victim’, or being in transient contact with bedding from the ‘victim’). DNA profiles attributable to the male or female known donors were obtained from 31% and 35% of the single and agglomerated bio-particles (putative cells) tested. The known male donor ‘assailant’ DNA profile was identified in the cell sampling from every mixture type tested. The results of this work demonstrate the efficacy of an alternative strategy to recover single source perpetrator DNA profiles in physical contact/assault cases involving trace perpetrator/victim cellular admixtures.     

Introduction to special section on the biological standard of living

In December 2008 the WOG Historical Demography organised a workshop at Ghent University that covered a wide range of topics from fertility trends and kinship characteristics to health issues. The presentations and discussions that took place at the workshop provided the inspiration for this special section on the biological standard of living. The articles in this section offer valuable contributions for three of those biological measures: height, mortality and cause of death. The introduction to the section demonstrates the significance of this particular kind of evidence for our understanding of social and economic history. Exploring and analysing the well-being of populations is one of the most interesting and main challenges of social scientists. As the articles in this special section show, using historical evidence on the health and height of a population is extremely important for our understanding of certain socio-economic processes, but also extremely complex.     

Sharing the benefits of biodiversity the Kani TBGRI deal in Kerala,India

Abstract

The United Nations Convention on Biological Diversity (CBD) concluded at the Earth Summit in 1992, mandates that where utilisation of the knowledge, innovations and practices of local and indigenous communities leads to benefits, such benefits shall be equitably shared with the holders of such knowledge, innovations and practices. The study analyses some of the issues that have emerged in the context of a ‘benefit sharing exercise’ attempted by the Tropical Botanic Garden and Research Institute (TBGRI), a research institute based in Kerala, with the Kani tribals of Kerala, pursuant to the development of a pharmaceutical drug, based on the knowledge, information and natural resources that the Kanis have nurtured over many years.

As the case study illustrates, the debate on benefit sharing in the absence of other fundamental rights such as the rights to land, access to the resource and adequate governance structures becomes a limited and myopic exercise. A ‘fair and equitable benefit sharing mechanism’ would therefore call for certain basic pre‐conditions that will be discussed in the course of the study.     

The convention on biological diversity: Ten years on and the strategic plan

Abstract

The Conference of the Parties to the Convention on Biological Diversity (Convention) has taken 114 decisions and launched programmes of work to address five biome‐based themes and thirteen cross‐cutting issues. The challenge for the Convention now is to demonstrate, through action and deed, that it is an effective vehicle for implementing this policy. In response to this challenge, the Conference of the Parties at its fifth meeting, in May 2000, decided to initiate a process to develop a Strategic Plan for the Convention that would provide an important mechanism for the implementation of this policy. This Note, which is an abridged version of document UNEP/CBD/MSP/2, has been prepared to assist participants in this Conference to provide more focused suggestions for the development of the Strategic Plan for the Convention.     

Costa Rica's biodiversity law: Sharing the process 1

Abstract

This article assesses the prospects for Costa Rica's new Biodiversity Law. We believe that this analysis could also provide a valuable case study of national implementation of the Convention on Biological Diversity (CBD). The article is not intended to be a primer on the CBD, nor will it defend its precepts. The authors believe that each nation must formulate a legal framework to regulate biodiversity that reflects their unique national circumstances.     

生物检材中的液化石油气成分的土顶空GC/MS分析

目的 建立测定人血中液化石油气(LPG)主要成分的定性定量方法。方法 将LPG添加到血中,用综合质谱图及保留时间定性、单离子法定量分析。结果LPG的7种主要成分血中最小检出限为12.8～31.3ng;仪器最小测量限为1.02～3.36ng。结论 土顶空-GC/MS法测定人血中LPG,简便、快速、准确,适用于LPG成分的检测。     

生物科技相关法律问题与《禁止生物武器公约》

生物技术所具有的人为改变生物自然性状的能力,也对生物多样性的保护构成了前所未有的威胁,并与人类社会的伦理观念发生了冲突。在专家学者、政府部门和各界的共同努力之下,发达国家目前已初步建立了生物安全规范体系。在国际范围内,联合国环境规划署制定了《国际生物技术安全准则》。为此, 我们必须加强对生物科技相关法律问题的研究。科学上的任何一样进步,人类都可以拿来作为武器。随着生物技术的飞速发展,在不久的将来很有可能会研制出杀伤力更隐蔽的新一代生物武器——基因武器。《禁止生物武器公约》对于禁止生物武器、防止生物武器扩散发挥了积极作用,已成为国际军控条约体系和以联合国为中心的集体安全框架的重要组成部分。中国政府一贯主张全面禁止和彻底销毁包括生物武器在内的一切大规模杀伤性武器,高度重视公约在维护世界和平与安全方面的积极作用。