'Smell of Death' Research Could Recover Bodies in Disasters and Solve Crimes

For years, cadaver dogs have been trained and used to detect and recover bodies in natural disasters. They are considered the gold standard but the time and effort put into training each dog is huge. As a result, forensic scientists have been trying to develop a portable device that uses the chemicals given off by decomposing bodies to find human bodies buried at crime scenes and in disasters. At the 238^th National Meeting of the American Chemical Society (ACS), Dr. Dan Sykes stated, “if there was a device that was as effective [as cadaver dogs] for a fraction of the cost, that would be something worth pursuing.” Dr. Dan Sykes has collaborated with Sarah A. Jones, a graduate student, to create this device that is so desperately needed.

In order to create this device scientists must first identify the gases that are given off by decomposing bodies not only under “perfect” conditions, but also under a variety of natural environmental conditions. Along with the identification of these chemical gases, a time sequence by hour and day must be included to figure out how long the body has been decomposing. When bodies go through decomposition, more than 30 chemical compounds are released such as putrescine and cadaverine, which both develop relatively early in the decomposition process.

Although some human bodies have been donated for testing, all the chemical compounds released cannot be recorded because the bodies are usually two to three days old. As a result, scientists have used pigs as models. According to Jones, pigs are good models because “they go through the same phases of decomposition as humans, as well as the same number of stages. And those stages last about as long in pigs as they do in humans before complete decomposition occurs and only the bones remain.” To perform their experiment, Sykes and Jones placed multiple pigs in different environmental conditions in specially designed odor-collecting units. Each unit was equipped with sensors known as solid phase micro extraction (SPME) fibers to capture gases. These fibers have been used in the past to sample the chemical composition of air. Odor data from the pigs was collected every six to twelve hours over the course of one week. From this testing, Sykes and Jones found that in days one to three precursors to indole are found and on the third day indole and putrescine are found. Sykes’ and Jones’ research is still on going (they are doing more experiments and tests) using a variety of different scenarios to re-construct the different ways human bodies could decompose, creating a more concrete picture of decomposition.

http://www.sciencedaily.com/releases/2009/08/090816211837.htm

Court Told of Possible Origin of DNA on a Police Baton By Kareem Fahim Feb 3, 2010

The news article “Court told of Possible Origin of DNA on a Police Baton” is a story about how a Police officer is on trial for sexually assaulting a Brooklyn man. It was said that he used his Police Baton to beat the man and assault him sexually. In Court Sarah Phillips a DNA specialist claimed that there was blood and genetic mix on the baton that could directly link the baton to the man who was beaten, Michael Mineo. Three New York Police officers are facing chargers. So far this piece of evidence seems it will be the key factor to put them away. Still, one of the lawyers for the officers stated that this find was “meaningless”. Phillips said that she was able to find the blood and DNA by swabbing the retractable portion of the Baton. She said that the DNA on the baton came from at least three contributors. This evidence helps prove that the Officers sexually assaulted Mineo by inserting the baton between his buttocks. It looks as if the police officers will be convicted due to this find in DNA. DNA has become extremely effective in solving cases.

Vindication Now Arrives After a Battle of 28 Years

The article “Vindication Now Arrives after Battle of 28 years” is about the story of Freddie Peacock and how he was found guilty of raping a woman outside his Rochester, NY apartment complex in 1976. He was convicted based on the woman’s testimonial evidence saying that he was her assailant and because of the fact that he had “confessed” during an unrecorded interview. The confession supposedly came about because he had not taken his schizophrenia and bipolar medication in five months and he later recanted his confession. Peacock was sentenced to 5 years in prison and since getting out had spent his time trying to clear his name. His name was only cleared after he had written to the Innocence Project, a group that works to clear the names of those wrongfully convicted using DNA evidence. On February 5, 2010, Freddie Peacock became the 250^th person to be cleared, by DNA evidence, of wrongful convictions.

http://www.nytimes.com/2010/02/05/nyregion/05dna.html

Forensic Identification of Tattoos

Forensic Identification of Tattoos

Biometric software helps to identify both perpetrators and victims. Tattoo recognition software can aid in these comparisons. The science of biometrics involves identification of people based on physical and behavioral characteristics. This includes facial recognition software, voice identification software and retina scanning. Biometrics is used commonly in forensic science with fingerprinting, handwriting analysis, hair analysis and blood identification.

Skin markings like scars, birthmarks and tattoos are considered soft biometrics, easily measurable physical characteristics that can change. Tattoos are becoming more common with estimates that approximately 36% of people between 18 and 29 have at least one tattoo. Most are specific to the individual, though many social groups adopt tattoos of similar design to designate membership. Tattoos can give information on social characteristics such as time in prison, number of crimes committed and ethnic affiliations.

For example, tattoos have been used for identifying bodies in mass disasters like 9/11 and homicides. This is often necessary when partial remains are found or other identifying biometrics like fingerprints are removed. Residual markings from tattoos remain in the skin even after burns or decomposition. Tattoos are also used to identify suspects in custody who may be using a false name.

Biometric scientists from Michigan State University developed software to aid in photographic tattoo identification. Tattoo images taken by law enforcement can be matched to existing images in photo databases which is much more efficient than a text-based search. The tattoos are matched using complex mathematical algorithms that compare similar characteristics. This allows matching when pictures may be blurred, such as those taken by a surveillance camera. Images are compared based on color, texture and shape of the tattoo.

http://forensicscience.suite101.com/article.cfm/forensic-identification-of-tattoos

DNA Deception

Last year Texas State officials were sued for storing infant blood sample without parental consent. The blood sample were said to have been for medical research into birth defects and childhood cancer. However, it has recently been learned that many of these sample where actually being used by the federal government to build a vast DNA database. Hundreds of blood sample were sent to the Armed Forces lab to build a national and, someday, international mitochondrial DNA (mtDNA) registry, to hopefully one day help crack missing persons and cold cases. Up until 2002 blood sample were simple thrown away but starting that year, the state health department began storing blood spots indefinitely, for “research into causes of selected diseases.” “State health officials never notified parents of the changes; they didn’t need consent for the birth-defect screening, so they didn’t ask for it for research purposes.” This has caused and uproar by many parents
From the parents point of view they are unaware of where their children’s DNA may end up. Unfortunately it might end up in the wrong persons hands and could come back to haunt there children later in life. As far as the database is concerned, it was a great idea to start up a new DNA database to be able to help forensic investigators solve cases later own down the road, if just should have been started with the parents consent.
Throughout the article they only talked about the database and how affective if could be briefly, it should have talked about the benefits that this database could provide more. In addition, the article doesn’t specifically state who was sued and by whom it just states that state officials were sued.

http://www.texastribune.org/stories/2010/feb/22/dna-deception/

Interesting Research on Pre-natal Embryos

Scientists at The Genome Institute of Singapore (GIS) and The Scripps Research Institute (TSRI), have developed some very interesting and new news. This study led an international effort to build a map that shows in detail how the human genome is modified during embryonic development. This is how the genetic code in humans is changed or modified in the pre-birth state. This detailed mapping is a significant move towards the success of targeted differentiation of stem cells into specific organs, which is a crucial consideration for stem cell therapy. Stem cell therapy in pre-natal embryos is and interesting forefront which could in time have the power to cure or determine genetic disorders in embryos. Scientists mapped a major component of the epigenome, DNA methylation, for the entire sequence of human DNA, and went further by comparing three types of cells that represented three stages of human development: human embryonic stem cells, human embryonic stem cells that were differentiated into skin-like cells, and cells derived from skin. With these comprehensive DNA methylome maps, scientists now have a blueprint of key epigenetic signatures associated with differentiation. DNA methylation causes specific subunits of DNA to be chemically modified, which controls which areas of the genome are active and which ones are dormant. DNA methylation is critical to the process in which embryonic cells change from "pluripotent stem cells," which have the ability to turn into hundreds of cell types, to "differentiated cells," distinct types of cells that make up different parts of the body, such as the skin, hair, nerves, etc. In reviewing the data produced by the study scientists were able to identify previously unknown patterns of DNA methylation. They identified cases in which DNA methylation appeared to enhance, rather than repress, the activity of the surrounding DNA, and found evidence to suggest a role for DNA methylation in the regulation of mRNA splicing.