How unique is each of us? What differentiates us as individuals from one another? How to “spot” the difference and identify of a person based on the DNA sample?
Nowadays DNA evidence is routinely used in criminal investigations, to identify genetic relationships between individuals, such as parent-child or between siblings as well as to identify victims in mass disasters. The analysis of DNA from ancient Egyptian mummies has shone some light onto relationships between Egyptian pharaoh Tutankhamun and ten of his relatives and even revealed details of their medical history. However, the results of this analysis weren’t readily accepted by the scientific community - there is a high risk of contamination of ancient DNA samples that may easily skew the final result [1].
The greatest portion of our DNA (99.9%) is identical to that of other people and only 0.1% is unique. It is that minute (but very important!) 0.1% of DNA that is a target of forensic research. Often there is only a trace amount of DNA available at the crime scene. This amount can still be enough for DNA analysis. The invention of polymerase chain reaction (PCR) in 1983 generally credited to Kary Mullis made it possible to produce thousands to millions of copies of a target fragment of DNA starting from very little amounts. It revolutionized science and became a “bread and butter” of many areas of biological research including forensic science.
In the 80s and 90s a series of female bodies were found in areas around the Green River in Washington State, USA. Chewing gum, cigarette butts and even traces of semen found at many sites were not sufficient for conviction. In 2003 the killer, Gary Ridgway, was finally caught when more sensitive forensic DNA tests finally matched Mr. Ridgway to semen found on women killed in 1982 and 1983 [2].
Join our DNA forensic lab led by Larry Melnick on February 1, 2020 and February 8, 2020. In the lab you will be provided with the samples designed to represent several suspects. The goal of the class is to use restriction enzymes to cut provided DNA samples at specific locations and compare the obtained “DNA profiles” to find out which of the suspects has a match to the DNA from the “crime scene”. In the process you will learn how to figure out for yourself "Who done it?" as well as what are the limitations of the technology and why DNA analysis should never be used as sole evidence in the criminal case.
Dr. Melnick worked for 25 years in biotechnology and pharmaceutical drug discovery including research at Collaborative Research Inc. and Sepracor, now Sunovion. He currently presides over the biotech start up, Embeca Biosciences LLC, working with RNA based solutions to drug targeting. Passionate speaker and experienced scientist, he brings his background working with recombinant DNA to the course on forensic DNA profiling.
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