DNA Double Down – JonBenet Ramsey
Describing the communications between Andy Horita, Investigator at the Boulder DA’s Office and DNA Custom Casework/Humanitarian Supervisor at Bode Technology, Angela Williamson, PhD., these memo entries speak in more detail about the amazing find by Bode of the same profile on the exterior waistband of the longJohns as exists in CODIS of the unknown male aka UM1.
On 5/21/08, at approximately 0933hours, I spoke with Williamson about the serological source of the touch DNA profile she developed from the exterior right and left sides of the white long johns worn by the victim. She stated that the scraping technique she used avoided any area of staining. She did not attempt to determine the serological source of the samples but did not believe that the source was saliva. Williamson did not believe that the DNA profiles from the exterior right and left portions of the victim’s long johns and the profile from the inside of the crotch of the underwear were both deposited via contamination from the autopsy table.
She noted that she believed the serological source of the DNA profile developed from the underwear was “probably saliva.”
On 6/12/08, at approximately 1444 hours, I spoke to Williamson and requested that she complete a statistical analysis of the profile she developed from the long underwear bottoms.
On 6/24/08, I received a report from Bode regarding the statistical probability of selecting a random, unrelated individual who would be included as a possible contributor to the mixture found on the exterior top right half of the white long underwear bottoms at four of the CODIS loci.
Unfortunately, this report was not included with all the CORAFiles, but at least part of it is printed here on the front page of the 6-20-2008 Bode Lab Report …
According to the SWGDAM Recommendations to the FBI Director on the “Interim Plan for the Release of Information in the Event of a ‘Partial Match’ at NDIS” …
When DNA profiles are compared, there are well-understood statistical patterns of expected allele sharing that can be calculated for unrelated as well as closely related individuals. These patterns of genetic sharing have been used in medical genetics as well as to help in the identification of disaster victims and missing persons. All of the genetic sharing between two DNA profiles can be distilled into a likelihood ratio that can then allow a statistical evaluation of how much more likely the match resulted from related versus unrelated individuals.
Evaluating the two samples, the right exterior longJohns profile and the profile in CODIS, this statistical probability seeks to answer these questions:
What is the probability of obtaining these DNA typing results if the POI is a contributor? And what is the probability of obtaining these results if the POI is not a contributor?
The Northeastern Association of Forensic Scientists NEAFS has produced the following training materials on probabilistic genotyping. These training materials were presented at Probabilistic DNA Mixture Interpretation Workshop: Likelihood Ratios for Mixture Samples 9-25-2015.
Likelihood Ratios – Single Contributor
Likelihood Ratios – Semi-continuous
Therefore, according to these documents the interpretation of the Bode Technology Lab Report 6-20-2008, the results of the exterior waistband sample can be read as follows:
The DNA typing results are about 6,200 times more probable if the DNA came from the Person of Interest (CODIS Profile) and an Unknown Contributor (Exterior Right Waistband Profile) than if the DNA came from two Unknown Contributors in the US Caucasian population.
The DNA typing results are about 12,000 times more probable if the DNA came from the Person of Interest (CODIS Profile) and an Unknown Contributor (Exterior Right Waistband Profile) than if the DNA came from two Unknown Contributors in the US African America population.
The DNA typing results are about 6,600 times more probable if the DNA came from the Person of Interest (CODIS Profile) and an Unknown Contributor (Exterior Right Waistband Profile) than if the DNA came from two Unknown Contributors in the US Southwest Hispanic population.
The DNA typing results are about 6,200 times more probable if the DNA came from the Person of Interest (CODIS Profile) and an Unknown Contributor (Exterior Right Waistband Profile) than if the DNA came from two Unknown Contributors in the US Southwest Hispanic population.