The forensic and investigative significance of reverse paternity testing with absent maternal sample

Abstract

The authors are involved in the extraction of DNA material from calcified tissues, oftentimes teeth, and analysis of such material to assist the investigative process, frequently by confirming the identity of the victim. Biologic or molecular techniques for the purposes of human identification have evolved to allow increasingly discriminating tests for use in criminal and noncriminal death investigations, as well as paternity disputes. The goal of such tests is to either include 2 samples (ie, they are from the same person, or in the case of paternity, they are from related individuals) or exclude 2 samples (ie, they are from different people or from unrelated individuals). Regardless of the system used and when data error has been eliminated, an exclusionary conclusion is irrefutable. The probability of excluding the falsely accused has steadily increased over the years as new methods are developed. Conventional ABO blood typing, for example, has a probability of exclusion (PE) of only 17%. This value increases to 53% with the inclusion of the Rh and MN systems. Additional serological markers can provide a probability of exclusion of greater than 99%. Today, the current method of choice for human identification is the polymerase chain reaction for the amplification of short tandem repeat (STR) multiplexes. This paper discusses the implications of nonpaternity in reverse paternity testing when only paternal DNA is available.