Keegan H.
Biology Per. 2
10/5
Crime Scene: # 2
Forensic Science Examined: Forensic Odontology
Summary of Science:
Forensic Odontology is the science of using dental records to identify unknown victims and suspects in criminal investigations. The first case of forensic odontology, in the US, was in 1692 during the Salem Witch Hunts. The court believed that a man named Reverend Burroughs bit his victims. The court brought him in and compared his bite to the bite marks on the victims and confirmed that that he was guilty. Many early cases involving the use of forensic dentistry used simple techniques. For example in 1954, the use of a block of cheese was used to determine if the suspect was guilty. In this case, a block of cheese was found at the crime scene with a bite taken out of it. The suspect was then asked to bite into a block of cheese in front of the court and the bite was compared to the block of cheese from the crime scene and found to be a match. By 1975 forensic dentists were using casts of molds of suspects and victims teeth to make a better representation of bite marks.
Teeth can be used to convict or to clear a suspect in a court case. Forensic odontologists examine the imprints on the victim to identify the suspect, this type of evidence is called associative evidence linking the crime to somebody. If a body is found, and there are teeth, the teeth will be x-rayed in a lab. The evidence found by an x-ray can be used to help concluded a case. Investigators need to be cautious using odontology as evidence because skin and other surfaces are malleable and can change the pattern of the bite. In 1999 a survey was conduct by the American Board of Forensic Odontology and it was found that two thirds of results were incorrect or inconclusive over a multiple year period. The Innocence Project stated, “the scarcity of research backing up bite mark comparisons played a role in a number of wrongful convictions over the years.” Today odontologists go through a long check list to identify victims or suspects correctly. Although there is still some controversy the process is always getting faster and more accurate.
The process scientists go through with dental identification is very scrupulous. When crimes happen sometimes the only real evidence they have is teeth. Teeth are durable and can survive centuries and extreme temperatures up to 1,200 degrees fahrenheit. Scientist look at any and all variables including implants, virgin teeth, cavities, and crowns to get a better picture of the victim.
Odontologists analyze every tooth and compare them using a computer to match the teeth down to the last nick. If the teeth are in good condition comparing the two sets of teeth is fairly easy. If the jaw is fractured or broken comparing the two can be more difficult because the teeth may be damaged or missing. Bite marks can be similar so scientists compare indents on skin where each tooth is located and how many teeth. If needed they may create a mold of the teeth and create a bite onto pig skin to use for comparison. Pig skin is similar to human skin so the teeth marks leave similar indentations.
Advances in dental health have also advanced forensic dental analysis. Teeth are healthier and are more durable. This makes comparing the sets of teeth even more reliable for the courts. Each year forensic odontology becomes more important, because it can determine many features about the person. If the victim has no dental records on file, odontologists can tell age and sex to narrow the search.
Conclusion: There were three victims that matched the entomology and anthropology reports. Using odontology, two of the victims were eliminated. Mitochondrial DNA confirmed it was Nathan Herron by linking the hair of his mother to him.
http://www.forensicmag.com/articles/2007/01/look-forensic-odontology
http://abcnews.go.com/blogs/health/2013/12/02/how-experts-identify-crash-victims-through-dental-records/
http://www.pbs.org/wgbh/pages/frontline/criminal-justice/real-csi/forensic-tools-whats-reliable-and-whats-not-so-scientific/
http://en.wikipedia.org/wiki/Forensic_dentistry
Keegan Hickerson
10/26
Per. 2
Crime Scene: # 2
Forensic Science Used: Nuclear DNA
Summary of Science:
Nuclear DNA is used to compare DNA between evidence and suspect or victims DNA. Sir Alec Jeffreys was the first person to develop DNA testing. Around the same time Polymerase Chain Reaction (PCR) was created. PCR is where scientist can extract and replicate DNA billions times. The FBI started using Nuclear DNA testing in 1998. Before that the testing was called serological testing, which also tested DNA. The one big difference between the two is that Nuclear DNA testing was more accurate.
The process with extracting DNA and replicating the DNA will result in what is know as a DNA fingerprint. Like a fingerprint the DNA is unique to that one person. The DNA is found in the Nucleus of a cell. Except for a select few cells, every cell as DNA. DNA fingerprints are very accurate, have hardly mistakes. Furthermore scientist need very little DNA to have successful replication. Some of the drawbacks of DNA testing is family member potentially will match up which causes issues. DNA has an overall negative charge due to the phosphate making up the rungs of the double helix.
The process for DNA testing starts with PCR. The DNA found at the crime scene must be extracted from the nucleus. The Lysis Buffer is added to the DNA. The lysis buffer contain water, soap, and salt. The purpose of the lysis buffer is to break down the lipids( fats) which make up the cellular membrane. The evidence and lysis buffer are strained removing any solid substances. The liquid is put into a test tube and 81% isopropyl alcohol is added. This makes the DNA clump together because the the alcohol is positive and the DNA negative. The DNA is removed for replication. The DNA is added to a special PCR tube. The tube is used to heat every part of the DNA, primers, nucleotides, and polymerase. The mixture is placed into a thermal cycler. The thermal cycler makes sure the DNA is properly heated and cooled. The first temperature is 95 degrees celsius which causes the DNA to separate from the double helix. Next, at 50 degrees celsius, the primers attach to the separated helices. The temperature is brought back to 72 degrees celsius, and the polymerase attach, enable for the DNA to replicate itself. The process is repeated billions of times until there is a large enough sample to begin the gel electrophoresis process.
Some of the advancements in Forensic Nuclear DNA testing are, the preserving and obtaining DNA, expanding databases, quality of test results. All these advancements continue making sure that DNA testing is as accurate as possible. If the DNA is not preserved correct it can ruin the entire test. Test continue to make sure there are is little error in the matching of the test results.
Conclusion:In crime scene 2, the PCR tests confirmed that the suspects were not the killers. There are now new suspects to examine.
http://omicsonline.org/recent-advances-in-forensic-dna-analysis-2157-7145.S12-001.pdf
http://en.wikipedia.org/wiki/Gel_electrophoresis
http://learn.genetics.utah.edu/content/labs/pcr/
http://www.wyndhamforensic.ca/resources/resources/Wfg_DNA_Nov09.pdf
http://www.fbi.gov/about-us/lab/biometric-analysis/dna-nuclear
Keegan Hickerson
Per.2
Crime scene: #2
Forensic science examined: forensic entomology
Summary of the science:
Forensic Entomology is when crime investigators use insects, who are attracted to decomposing bodies, to determine how long ago somebody died, how an injury was inflicted, as well as where it happened. Entomology can also tell whether drugs or poison were involved. There are three sub groups of entomology, urban, stored and medico-legal. Urban entomology involves pests infestations in buildings requiring litigation often involving landlords. Stored entomology involves commercially distributed food. Medico-legal involves murder, decomposing bodies,and evidence gathering of insects.
Medico- legal Forensic Entomology has been used since the 14th century but has only been used within the legal system since 1990’s and is now considered a reliable source of evidence. Several scientist helped further the development of entomology. One of those scientist was Francesco Redi who helped prove the value entomology. In 1660’s people believed that insects could appear out of dust and other abiotic materials. He disproved this theory, of spontaneous generation, by conducting a series of experiments. Along with Francesco Redi, Song Ci, Bergeret d’Arbois, Jean Pierre Mégnin and Hermann Reinhard all contributed to the advancements of entomology through research and experimentation. Bergeret d’Arbois was the first to apply entomology to forensics in 1855. He used the life cycle and life length of insects to determine the length between when the person died and when the person was found also called the postmortem interval (PMI) of a victim.
The techniques used to analyze insects are scanning electron microscope, potassium pergamente, and mitochondrial DNA. Entomologist can extract human DNA from the larvae and adult insects to determine the victim's identity. Scanning with an electron microscope(SEM) is used to identify the species of insect eggs to determine when PMI(postmortem interval). Potassium pergamente is a faster more affordable way to test insects when electron microscopes are not available.
It is helpful to determine whether the body has been dead for a month or more, to narrow the number and type of insects on the corpse. If the victim has been dead less than a month, scientist can determine PMI within a few days of the death. The entomologist is called in to collect eggs, maggots, pupae , pupae cases, adult flies, beetles, and other insects. The scientist carefully collect the specimens for evaluation. These specimens are analyzed for the metamorphic stage in which the insect is in to closer determine the PMI. The entomologist can then conclude more accurately the date of death. Conditions can also affect the PMI. Moisture, heat, air, geography, and water exposure can all affect the amount and varieties of the insects and their rate of development.
Some of the advancements in forensic entomology are the speed and accuracy of the test results. The electron microscope has been a recent advancement, telling scientist exactly what species where on the body. Electron microscopes help with identification of species, this results in greater accuracy in species identification, therefore more reliable evidence. Also, more courts have been accepting entomology as a reliable source of evidence.
Conclusion:The test was conducted to determine how long ago the man died and what type of insect species was found. The insects found on the victim were dermestid beetles. The skeletal remains were completely dry so this means the victim had been dead for 1-3 years. Through the tests of anthropology and entomology the victims list narrowed to Nathan Herron and Andrew Ahonen.
http://en.wikipedia.org/wiki/Forensic_entomology#Forensic_entomology_subfields
http://www.slideshare.net/Nagwa2012/forensic-entomology-past-present-and-the-future
http://www.nhm.ac.uk/resources-rx/files/22feat_maggots_and_murders-7201.pdf
http://www.ncbi.nlm.nih.gov/pubmed/12455660
Jerry Lee Jenkins
Conviction: First Degree Rape and First Degree Sexual Assault.
Sentence: 2 Life Sentences
Date of Imprisonment: 1987
Date of Exoneration: 6/7/13
Reason for Wrongful Conviction: Eyewitness Misidentification
Evidence Leading to Exoneration:
Reexamination of DNA and the Evidence Found
Biology Per. 2
10/5
Crime Scene: # 2
Forensic Science Examined: Forensic Odontology
Summary of Science:
Forensic Odontology is the science of using dental records to identify unknown victims and suspects in criminal investigations. The first case of forensic odontology, in the US, was in 1692 during the Salem Witch Hunts. The court believed that a man named Reverend Burroughs bit his victims. The court brought him in and compared his bite to the bite marks on the victims and confirmed that that he was guilty. Many early cases involving the use of forensic dentistry used simple techniques. For example in 1954, the use of a block of cheese was used to determine if the suspect was guilty. In this case, a block of cheese was found at the crime scene with a bite taken out of it. The suspect was then asked to bite into a block of cheese in front of the court and the bite was compared to the block of cheese from the crime scene and found to be a match. By 1975 forensic dentists were using casts of molds of suspects and victims teeth to make a better representation of bite marks.
Teeth can be used to convict or to clear a suspect in a court case. Forensic odontologists examine the imprints on the victim to identify the suspect, this type of evidence is called associative evidence linking the crime to somebody. If a body is found, and there are teeth, the teeth will be x-rayed in a lab. The evidence found by an x-ray can be used to help concluded a case. Investigators need to be cautious using odontology as evidence because skin and other surfaces are malleable and can change the pattern of the bite. In 1999 a survey was conduct by the American Board of Forensic Odontology and it was found that two thirds of results were incorrect or inconclusive over a multiple year period. The Innocence Project stated, “the scarcity of research backing up bite mark comparisons played a role in a number of wrongful convictions over the years.” Today odontologists go through a long check list to identify victims or suspects correctly. Although there is still some controversy the process is always getting faster and more accurate.
The process scientists go through with dental identification is very scrupulous. When crimes happen sometimes the only real evidence they have is teeth. Teeth are durable and can survive centuries and extreme temperatures up to 1,200 degrees fahrenheit. Scientist look at any and all variables including implants, virgin teeth, cavities, and crowns to get a better picture of the victim.
Odontologists analyze every tooth and compare them using a computer to match the teeth down to the last nick. If the teeth are in good condition comparing the two sets of teeth is fairly easy. If the jaw is fractured or broken comparing the two can be more difficult because the teeth may be damaged or missing. Bite marks can be similar so scientists compare indents on skin where each tooth is located and how many teeth. If needed they may create a mold of the teeth and create a bite onto pig skin to use for comparison. Pig skin is similar to human skin so the teeth marks leave similar indentations.
Advances in dental health have also advanced forensic dental analysis. Teeth are healthier and are more durable. This makes comparing the sets of teeth even more reliable for the courts. Each year forensic odontology becomes more important, because it can determine many features about the person. If the victim has no dental records on file, odontologists can tell age and sex to narrow the search.
Conclusion: There were three victims that matched the entomology and anthropology reports. Using odontology, two of the victims were eliminated. Mitochondrial DNA confirmed it was Nathan Herron by linking the hair of his mother to him.
http://www.forensicmag.com/articles/2007/01/look-forensic-odontology
http://abcnews.go.com/blogs/health/2013/12/02/how-experts-identify-crash-victims-through-dental-records/
http://www.pbs.org/wgbh/pages/frontline/criminal-justice/real-csi/forensic-tools-whats-reliable-and-whats-not-so-scientific/
http://en.wikipedia.org/wiki/Forensic_dentistry
Keegan Hickerson
10/26
Per. 2
Crime Scene: # 2
Forensic Science Used: Nuclear DNA
Summary of Science:
Nuclear DNA is used to compare DNA between evidence and suspect or victims DNA. Sir Alec Jeffreys was the first person to develop DNA testing. Around the same time Polymerase Chain Reaction (PCR) was created. PCR is where scientist can extract and replicate DNA billions times. The FBI started using Nuclear DNA testing in 1998. Before that the testing was called serological testing, which also tested DNA. The one big difference between the two is that Nuclear DNA testing was more accurate.
The process with extracting DNA and replicating the DNA will result in what is know as a DNA fingerprint. Like a fingerprint the DNA is unique to that one person. The DNA is found in the Nucleus of a cell. Except for a select few cells, every cell as DNA. DNA fingerprints are very accurate, have hardly mistakes. Furthermore scientist need very little DNA to have successful replication. Some of the drawbacks of DNA testing is family member potentially will match up which causes issues. DNA has an overall negative charge due to the phosphate making up the rungs of the double helix.
The process for DNA testing starts with PCR. The DNA found at the crime scene must be extracted from the nucleus. The Lysis Buffer is added to the DNA. The lysis buffer contain water, soap, and salt. The purpose of the lysis buffer is to break down the lipids( fats) which make up the cellular membrane. The evidence and lysis buffer are strained removing any solid substances. The liquid is put into a test tube and 81% isopropyl alcohol is added. This makes the DNA clump together because the the alcohol is positive and the DNA negative. The DNA is removed for replication. The DNA is added to a special PCR tube. The tube is used to heat every part of the DNA, primers, nucleotides, and polymerase. The mixture is placed into a thermal cycler. The thermal cycler makes sure the DNA is properly heated and cooled. The first temperature is 95 degrees celsius which causes the DNA to separate from the double helix. Next, at 50 degrees celsius, the primers attach to the separated helices. The temperature is brought back to 72 degrees celsius, and the polymerase attach, enable for the DNA to replicate itself. The process is repeated billions of times until there is a large enough sample to begin the gel electrophoresis process.
Some of the advancements in Forensic Nuclear DNA testing are, the preserving and obtaining DNA, expanding databases, quality of test results. All these advancements continue making sure that DNA testing is as accurate as possible. If the DNA is not preserved correct it can ruin the entire test. Test continue to make sure there are is little error in the matching of the test results.
Conclusion:In crime scene 2, the PCR tests confirmed that the suspects were not the killers. There are now new suspects to examine.
http://omicsonline.org/recent-advances-in-forensic-dna-analysis-2157-7145.S12-001.pdf
http://en.wikipedia.org/wiki/Gel_electrophoresis
http://learn.genetics.utah.edu/content/labs/pcr/
http://www.wyndhamforensic.ca/resources/resources/Wfg_DNA_Nov09.pdf
http://www.fbi.gov/about-us/lab/biometric-analysis/dna-nuclear
Keegan Hickerson
Per.2
Crime scene: #2
Forensic science examined: forensic entomology
Summary of the science:
Forensic Entomology is when crime investigators use insects, who are attracted to decomposing bodies, to determine how long ago somebody died, how an injury was inflicted, as well as where it happened. Entomology can also tell whether drugs or poison were involved. There are three sub groups of entomology, urban, stored and medico-legal. Urban entomology involves pests infestations in buildings requiring litigation often involving landlords. Stored entomology involves commercially distributed food. Medico-legal involves murder, decomposing bodies,and evidence gathering of insects.
Medico- legal Forensic Entomology has been used since the 14th century but has only been used within the legal system since 1990’s and is now considered a reliable source of evidence. Several scientist helped further the development of entomology. One of those scientist was Francesco Redi who helped prove the value entomology. In 1660’s people believed that insects could appear out of dust and other abiotic materials. He disproved this theory, of spontaneous generation, by conducting a series of experiments. Along with Francesco Redi, Song Ci, Bergeret d’Arbois, Jean Pierre Mégnin and Hermann Reinhard all contributed to the advancements of entomology through research and experimentation. Bergeret d’Arbois was the first to apply entomology to forensics in 1855. He used the life cycle and life length of insects to determine the length between when the person died and when the person was found also called the postmortem interval (PMI) of a victim.
The techniques used to analyze insects are scanning electron microscope, potassium pergamente, and mitochondrial DNA. Entomologist can extract human DNA from the larvae and adult insects to determine the victim's identity. Scanning with an electron microscope(SEM) is used to identify the species of insect eggs to determine when PMI(postmortem interval). Potassium pergamente is a faster more affordable way to test insects when electron microscopes are not available.
It is helpful to determine whether the body has been dead for a month or more, to narrow the number and type of insects on the corpse. If the victim has been dead less than a month, scientist can determine PMI within a few days of the death. The entomologist is called in to collect eggs, maggots, pupae , pupae cases, adult flies, beetles, and other insects. The scientist carefully collect the specimens for evaluation. These specimens are analyzed for the metamorphic stage in which the insect is in to closer determine the PMI. The entomologist can then conclude more accurately the date of death. Conditions can also affect the PMI. Moisture, heat, air, geography, and water exposure can all affect the amount and varieties of the insects and their rate of development.
Some of the advancements in forensic entomology are the speed and accuracy of the test results. The electron microscope has been a recent advancement, telling scientist exactly what species where on the body. Electron microscopes help with identification of species, this results in greater accuracy in species identification, therefore more reliable evidence. Also, more courts have been accepting entomology as a reliable source of evidence.
Conclusion:The test was conducted to determine how long ago the man died and what type of insect species was found. The insects found on the victim were dermestid beetles. The skeletal remains were completely dry so this means the victim had been dead for 1-3 years. Through the tests of anthropology and entomology the victims list narrowed to Nathan Herron and Andrew Ahonen.
http://en.wikipedia.org/wiki/Forensic_entomology#Forensic_entomology_subfields
http://www.slideshare.net/Nagwa2012/forensic-entomology-past-present-and-the-future
http://www.nhm.ac.uk/resources-rx/files/22feat_maggots_and_murders-7201.pdf
http://www.ncbi.nlm.nih.gov/pubmed/12455660
Jerry Lee Jenkins
Conviction: First Degree Rape and First Degree Sexual Assault.
Sentence: 2 Life Sentences
Date of Imprisonment: 1987
Date of Exoneration: 6/7/13
Reason for Wrongful Conviction: Eyewitness Misidentification
Evidence Leading to Exoneration:
Reexamination of DNA and the Evidence Found