Subjectivity and bias in forensic DNA mixture interpretation

The objectivity of forensic science decision making has received increased attention and scrutiny. However, there are only a few published studies experimentally addressing the potential for contextual bias. Because of the esteem of DNA evidence, it is important to study and assess the impact of subjectivity and bias on DNA mixture interpretation. The study reported here presents empirical data suggesting that DNA mixture interpretation is subjective. When 17 North American expert DNA examiners were asked for their interpretation of data from an adjudicated criminal case in that jurisdiction, they produced inconsistent interpretations. Furthermore, the majority of 'context free' experts disagreed with the laboratory's pre-trial conclusions, suggesting that the extraneous context of the criminal case may have influenced the interpretation of the DNA evidence, thereby showing a biasing effect of contextual information in DNA mixture interpretation.     

The use of Hemastix® severely reduces DNA recovery using the BioRobot® EZ1

Abstract: The choice of reagents for presumptive tests for blood, and subsequent extraction methodologies, can significantly affect both the quantity and quality of purified DNA. Blood samples directly tested with Hemastix^® yielded <1% of the DNA recovered from untested samples when purified using the Qiagen BioRobot^® EZ1 and EZ1^® DNA Investigator kit. Full short tandem repeat profiles were obtained from both tested and untested samples, suggesting that the Hemastix^® reagent(s) affect DNA binding, rather than produce DNA damage. The Hemastix^® inhibition of DNA yield could be overcome by the addition of MTL buffer to the sample prior to extraction. Laboratories may wish to modify current procedures for extracting blood samples, utilize other extraction/purification methodologies, or inform their submitting agencies to avoid direct exposure of questioned bloodstains to Hemastix^® reagents.     

Genetic variation at 15 autosomal microsatellite loci in the three highly endogamous tribal populations of Orissa, India

Although microsatellite diversity in autosomal chromosomes has been extensively described for many of the Indian populations, there is still a lacuna left on information about the genetic diversity of tribal populations. This paper reports the genetic data on the three tribal populations belonging to the Austroloid ethnic group from Orissa (Juang, Paroja and Saora). The 15 STR (D3S1358, THO1, D21S11, D18S51, PentaE, D5S818, D13S317, D7S820, D16S539, CSF1PO, PentaD, vWA, D8S1179, TPOX, FGA) polymorphism would help to accentuate the STR database for better understanding of population genetics and forensic applications. The microsatellites included in the system are found to be highly polymorphic, with the combined power of exclusion being greater than 0.999, in all the three investigated populations.     

法医DNA技术破获"人头"分尸案1例

１９９７年１月２８日，一环卫工人在垃圾处理场发现一个被刀分割的人头。经查找到最早发现“人头”的人，当时“人头”在城关一间垃圾屋内（发现人以为是猴头），该屋窗口有新鲜血迹和头发，分析为凌晨抛尸（因垃圾屋每日都清理）。对“人头”进行勘验，发现头发被剪短，耳、鼻、眼及脸上的肉均被割掉，经骨骼分析及XY染色体性别检验，初步判定死者为女性，一度工作陷入僵局。进一步进行DNA性别鉴定和颅骨容貌复原，性别结论是：死者为男性，由于性别判定的正确确定，使侦查工作又有了新的起色。１９９９年８月，浙江人杨某反映，称其弟…     

生物样品中杀鼠迷(Coumatetralyl)液相色谱检测的实验研究

本文经实验研究,确定了在酸性条件下用氯仿作为萃取剂,萃取液经酸性氧化铝柱净化,分段收集冼脱液的方法,使杀鼠迷回收率在不低于70%的基础上,脂肪及其它杂质近乎完全清除。杀鼠迷的检测采用高效液相色谱法(HPLC),紫外检测灵敏度达10~(-9)g。并对杀鼠迷中毒家兔的尿液进行了分析,发现一次性服用20mg/kg 体重的家兔,在45h 的尿液中,尚能检出其原形物。     

25例医疗纠纷的法医临床学鉴定回顾性分析

目的探讨医疗纠纷的法医临床学鉴定及其相关问题。方法对25例医疗纠纷案例资料进行了回顾性整理分析。结果医疗失误16例,其中有不良后果的10例,均发生于手术科室;无医疗失误9例。结论医疗纠纷法医学鉴定过程中认定医疗失误是基础,认定医疗失误与不良后果的关系是关键。