Characterization of human DNA in environmental samples

Environmental samples from indoor surfaces can be confounded by dust, which is composed largely of human skin cells and has been documented to contain roughly tens of micrograms of total DNA per gram of dust. This study complements previous published work by providing estimates of the quantity of amplifiable human DNA found in environmental samples from a typical indoor environment, categorized by the intensity of human traffic and visible quantity of dust. Dust was collected by surface swabbing standard 576 cm² areas in eight locations, and evaluated for total DNA quantity, presence of human DNA (mitochondrial and nuclear loci using conventional PCR), quantity of human nuclear DNA using quantitative PCR, and STR analysis. The total DNA content of 36 dust samples ranged from 9 to 28 ng/cm², and contained 0.2–1.1 pg/cm² of human DNA. Overall, human DNA was detected in 97% of 36 dust samples and 61% of samples yielded allele distributions of varying degrees of complexity when subjected to STR analysis. The implications of this study are twofold. First, the presence of dust in evidence can be a significant contamination source in forensic investigations because the human DNA component is of sufficient quality and quantity to produce allele calls in STR analysis. This can be effectively managed by implementing stringent protocols for collection and analysis of potential biological samples. A second implication is the use of dust as a source of evidence for identification of inhabitants within a defined location. In the latter case, a number of additional studies would be necessary to identify relevant pretreatments for environmental dust samples and to develop the necessary deconvolution techniques to separate the composite genotypes obtained.     

The Wanderers

Dr. Jeffreys writes to say that he would be interested to hearof any other tribe whose name is a sobriquet for "wanderer"or "stranger". He has not dealt with Southern Africa, and wewould therefore suggest Angoni. Any reader who can add to thelist may care to get into touch with the writer of this articleat Bamenda, British Cameroons.     

Organizational Process,Rulemaking Pace,and the Shadow of Judicial Review

Scholars have long understood that structuring internal work processes into more hierarchical or team‐based arrangements has consequences for organizational outputs. Building on this insight, this research examines the relationship between how agencies organize their rulemaking routines and the resulting rules. Tracking the job functions of rule contacts for economically significant rules proposed over a four‐year period, the analysis demonstrates that expanding the breadth of personnel types closely involved in a rulemaking is associated with a reduction in the time it takes to promulgate the rule. However, increasing the pace at which rules are finalized is not without cost, as those completed faster appear more likely to be overturned when challenged in court. The article not only adds another dimension to empirical scholarship studying rulemaking, which has largely focused on how forces originating outside the agency affect rules, but also suggests the importance of considering competing priorities in designing rulemaking processes.