Dr. Heather Degnan, Forensic Science Examiner and Supervising DNA Analyst at the Connecticut Forensic Science Laboratory, presented a PowerPoint show to 69 Y’s Men of Meriden on Tuesday, April 8, describing the complex subject of forensic DNA analysis. Those attending had to pay close attention to follow the intricacies of this relatively new science used in solving crimes.
Degnan first noted that DNA is found in the nucleus and in the cytoplasmic mitochondria of cells. No two humans have the same DNA make-up, except for identical twins. This allows a virtually infallible way to identify an individual. The use of DNA testing began about 1980, and in 1988 the FBI created the Combined DNA Index System database, today present not only nationally but also in each state; this database currently contains DNA profiles on 13 million individuals. A DNA sample is collected on every convicted felon.
Specimens for forensic analysis include blood, semen, saliva, urine, hair, teeth and bone. The process has become so sophisticated that only one nanogram (one billionth of a gram) of material is required. The analytical process starts with obtaining the sample (perhaps a fingernail or saliva from a cigarette butt), extracting the material, purifying the sample, duplicating the sample many times over to create enough material to analyze, then separation and identification, and finally statistical interpretation. This multistage process can today be accomplished in as little as 18 hours.
Specimens may be obtained from a variety of sources, including bite marks, shoe prints, facial scratches or material under a victim’s fingernails. Evaluation is often complicated by either contamination of the sample or the presence of multiple DNA profiles in the specimen. The state lab is located on Colony St. in Meriden, utilizing the services of 26 DNA analysts who last year processed about 1300 DNA requests.
Retired or semi-retired men from Meriden or surrounding communities, interested in attending a Y’s Men of Meriden meeting, are invited to call (203) 238-7784 or visit the www.ysmenofmeriden.com website.