dna typing

Mitochondrial DNA Typing in Forensics

Posted on by Anupama Gopalakrishnan

23540687_lMitochondria, often thought of as powerhouses of the cell, are fascinating eukaryotic organelles with a double-layered membrane and their own genome. Mitochondrial DNA (Mt DNA) is typically about 16570 bases, circular, highly compact, haploid and contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation, a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell’s main energy currency. The remaining genes code for transfer RNA (tRNA) and ribosomal RNA (rRNA) which are necessary for translating messenger RNA transcribed from nuclear DNA, into protein molecules.

One of the most important characteristics of mitochondrial genome that is relevant to field of forensics is the copy number. Continue reading “Mitochondrial DNA Typing in Forensics”

DNA Typing Confirms Bronze Age Mix-and-Match Burials

Posted on by Terri Sundquist

Archaeologists have made an interesting discovery while excavating the late Bronze Age/early Iron Age settlement named Cladh Hallan on the island of South Uist in the Outer Hebrides, Scotland. They have uncovered four human skeletons buried at regular intervals beneath three roundhouses dating from the 11th century BC: an adult male, an adult female, a 10–14-year-old girl and a 3-year-old child. The careful arrangement of these burials directly below the roundhouses led archaeologists to initially hypothesize that these might be foundation burials—an ancient practice in which people, usually younger people, were sacrificed and buried under a building’s foundation in the belief that their blood and spirit would protect and strengthen the building and building site. As strange as that custom seems to us, it gets weirder. Two of these skeletons showed signs of mummification and contained skeletal elements from multiple individuals intentionally pieced together to form intact skeletons. Continue reading “DNA Typing Confirms Bronze Age Mix-and-Match Burials”

Not My Shade of DNA

Posted on by Terri Sundquist

LipstickDNA testing is providing some answers in a nine-month campaign of hate and revenge involving two British women: a wife and her husband’s mistress. Between May of 2010 and February of 2011, the wife was stabbed in the stomach with a screwdriver, had bleach thrown in her face, received death threats in the mail, been the victim of an arson attack and had a threatening message written on her apartment window in lipstick. She blamed the mistress in her reports to police. As a result, the mistress had been arrested numerous times and spent 20 hours in police custody despite her assertions that she was not involved in any of the attacks. The situation became so maddening that her family started a diary of her whereabouts to help prove her innocence.

Hoping to find some physical evidence that might shed some light on the events, police examined the evidence in the case more closely. This included DNA analysis of the lipstick used to write the threatening message and saliva used to seal the envelope containing the death threats. The results of the DNA analysis were shocking. Continue reading “Not My Shade of DNA”

How to Catch a Serial Killer

Posted on by Terri Sundquist

A Lear jet“[I]deas about who killed whom does not come to the criminal profiler in flashes of insight, nor does a group of FBI profilers fly around the country in a Lear jet and solve heinous murders within a few days with the help of a computer genius back in Quantico who seemingly has unlimited resources and who admittedly conducts illegal hacking into data banks that are highly confidential.”

This excerpt from a recent Forensic Science International paper (1) pokes fun at criminal profiling as portrayed on television shows such as Criminal Minds. However, this is just another example of Hollywood producers embellishing reality and stretching the truth to try to increase the entertainment value. [To learn about how the television show CSI has warped public perception of the forensic sciences, check out The Reality of Crime Scene Investigation. Part I: Common Myths].

So, if these Criminal Minds and CSI approaches to catching murderers aren’t accurate, how do law enforcement officers identify killers and bring them to justice? Continue reading “How to Catch a Serial Killer”

Justice 27 Years Too Late: The William Dillon Story

Posted on by Terri Sundquist

Balance of justiceWilliam (Bill) Dillon spent more than half of his life in a prison for a crime he did not commit. Now, after being exonerated by DNA testing, he is telling his story of injustice and, eventually, freedom. On Wednesday, January 12, he visited Promega Corporation in Madison, Wisconsin, to relate his story and his efforts as an advocate for exonerees who are released from prison with little support from the same justice system that failed them in the first place.

The events that lead to Dillon’s false imprisonment started on August 17, 1981, when a man was found beaten to death in the parking area of a beach in a Florida tourist town. On August 22, detectives were investigating the crime scene, when Dillon and his brother drove into the parking area. Little did Dillon know that his decision to drive to the beach that day would lead to a wrongful conviction and 27 years and 8 months in prison.

Continue reading “Justice 27 Years Too Late: The William Dillon Story”