Genetic structure among 38 populations from the United States based on 11 U.S. core Y chromosome STRs

A DNA database consisting of the 11 Y chromosome short-tandem-repeat (Y-STR) recommended by the Scientific Working Group on DNA Analysis Methods is constructed for 2517 individuals from 38 populations in the United States. The population samples derive from five ethnic groups currently living in 10 states. A multidimensional scaling (MDS) plot places the populations into four discrete clusters (African Americans (AA), European Americans (EA), Hispanic Americans (HA), and Asian Americans (SA)) and one dispersed cluster of Native Americans. An analysis of molecular variance (AMOVA) indicates that a large proportion of the total genetic variance is partitioned among ethnic groups (24.8%), whereas only a small amount (1.5%) is found among-populations within ethnic groups. Separate AMOVA analyses within each ethnic group show that only the NA sample contains statistically significant among-population variation. Pair wise population differentiation tests do uncover heterogeneity among EA and among HA populations; however, this is due to only a single sample within each group. The analyses support the creation of AA, EA, HA, and Asian American databases in which samples from different geographic regions within the United States are pooled. We recommend that separate databases be constructed for different NA groups.     

Asking the Gatekeepers: A National Survey of Judges on Judging Expert Evidence in a Post-Daubert World

Drawing on the responses provided by a survey of state court judges (N = 400), empirical evidence is presented with respect to judges' opinions about the Daubert criteria, their utility as decision-making guidelines, the level to which judges understand their scientific meaning, and how they might apply them when evaluating the admissibility of expert evidence. Proportionate stratified random sampling was used to obtain a representative sample of state court judges. Part I of the survey was a structured telephone interview (response rate of 71%) and in Part II, respondents had an option of completing the survey by telephone or receiving a questionnaire in the mail (response rate of 81%). Survey results demonstrate that judges overwhelmingly support the gatekeeping role as defined by Daubert, irrespective of the admissibility standard followed in their state. However, many of the judges surveyed lacked the scientific literacy seemingly necessitated by Daubert. Judges had the most difficulty operationalizing falsifiability and error rate, with only 5% of the respondents demonstrating a clear understanding of falsifiability and only 4% demonstrating a clear understanding of error rate. Although there was little consensus about the relative importance of the guidelines, judges attributed more weight to general acceptance as an admissibility criterion. Although most judges agreed that a distinction could be made between scientific and technical or otherwise specialized knowledge, the ability to apply the Daubert guidelines appeared to have little bearing on whether specific types of expert evidence were designated as science or nonscience. Moreover, judges' bench philosophy of science seemed to reflect the rhetoric, rather than the substance, of Daubert. Implications of these results for the evolving relationship between science and law and the ongoing debates about Frye, Daubert, Joiner, and Kumho are discussed.