Evaluation of Hinf I-generated VNTR profile frequencies determined using various ethnic databases

Abstract

Concerns have been raised about hypothetical problems arising from the use of statistics for determining the likelihood of occurrence of DNA profiles for forensic purposes. A major contention is that reference databases based on subgroups of a major population category rather than on general (or major) population groups, might yield large differences in the estimated likelihood of occurrence of DNA profiles. This hypothetical issue is based on the assertion by some people that the differences among subgroups within a race would be greater than between races (at least for forensic purposes). To evaluate the effects of the above concern the likelihood of occurrence of 615 Hinf I-generated target DNA profiles was estimated using fixed bin frequencies from various ethnic databases and the multiplication rule. Based on the data in this study, differences in allele frequencies at a particular locus do not have substantial effects on VNTR profile frequency estimates when subgroup reference databases from within a major population group are compared. In contrast, the greatest variation in statistical estimates occurs across-major population groups. Therefore, the assertion, by some critics that the differences among subgroups within a race would be greater than between races (at least for forensic purposes), is unfounded. The data in the study support that comparisons across major population groups provide valid estimates of DNA profile frequencies without forensically significant consequences. The data do not support the need for alternate procedures, such as the ceiling principle approach, for deriving statistical estimates of DNA profile frequencies.