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DNA - Victims Speak From the Grave - Part 1
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Who do they speak for?
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09/13/2008
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Paper By: Howard Taylor
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 DNA Helix
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The science of DNA testing has become the Holy Grail of innocence verses guilt or guilt verses innocence. Arguably, whether DNA evidence is good or
bad depends on which side of the courtroom one sits. To prosecutors it can be a cruise missile in the coffin for a defendant but for the defense it equates to GOD's
hand striking at tyranny. In the U.S. society and others around the world DNA evidence often times is the final word.
I am not a scientist nor am I an expert on DNA. What follows will be parts of articles combined from many sources that go into detail about what DNA is. We will study
the history of the development of the technology and how it is used in our world. We will also discuss topics such as the DNA database and the abuse of DNA evidence by
government agencies.
Note: LawReport.org has a web page dedicated to Innocence Projects.
These organizations are dedicated to freeing persons wrongly convicted and imprisoned. DNA testing has proven to be an invaluable tool in their efforts.
This article may evolve over time. Additions or changes will be noted with red text. Please check back often because issues so closely
associated with science change frequently.
[1] Who invented DNA testing?
Sir Alec John Jeffreys, FRS (born 9 January 1950 at Oxford in Oxfordshire) is a British
geneticist, who developed techniques for DNA fingerprinting and DNA profiling which are now used all over the world in forensic science to assist police detective
work, and also to resolve paternity and immigration disputes. He is a professor of genetics at the University of Leicester, and he became an honorary freeman of the
City of Leicester on 26 November 1992. In 1994, he was knighted by her Majesty Queen Elizabeth II of England, for Services to Science and Technology.
Jeffreys graduated in biochemistry from Merton College. He enjoys being at the laboratory bench, and prepared his PhD thesis entitled "Studies on the mitochondria of
cultured mammalian cells" as a postgraduate student at the Genetics Laboratory, University of Oxford. After finishing his PhD, he moved to the University of Amsterdam,
where he worked on mammalian genes as a research fellow. He moved on to the University of Leicester in 1977, where he found an academically stimulating and helpful
environment, and where he invented and developed genetic fingerprinting.
[1] Genetic fingerprinting
Jeffreys had a "eureka moment" in his lab in Leicester after looking at the X-ray of a DNA experiment at 9:05 am on Monday 10 September 1984, which unexpectedly showed both
similarities and differences in his technician's family's DNA. Within about half an hour, he realized the possible scope of DNA fingerprinting, which uses variations in the
genetic code to identify individuals. The method has become important in forensic science to assist police detective work, and it has also proved useful in resolving
paternity and immigration disputes. The method can also be applied to non-human species, for example in wildlife population genetics studies. Before his methods were
commercialised in 1987 his laboratory was the only centre carrying out DNA fingerprinting in the world, and during this period of about two or three years it was very busy,
receiving inquiries from all over the globe.
Jeffreys' DNA method, which is often called DNA fingerprinting, was first put to use when he was asked to help in a disputed immigration case to confirm the identity of a
British boy whose family was originally from Ghana. The case was resolved when the DNA results proved that the boy was closely related to the other members of the family,
and Jeffreys saw the relief in the mother's face when she heard the results. DNA fingerprinting was first used as a police forensic test to identify the rapist and
killer of two teenagers, Lynda Mann and Dawn Ashworth, who were both murdered in Narborough, Leicestershire, in 1983 and 1986 respectively. Colin Pitchfork was identified
and convicted of murder after samples taken from him matched semen samples taken from the two dead girls. This turned out to be a specifically important identification for
without it, British Authorities believe it was inevitable Richard Buckland, the main suspect at the time, would have been found guilty, so not only did Jeffrey's work
in this case prove who the real killer was, but exonerated someone who likely would have spent his life in prison otherwise. Another early achievement was to confirm the
identity for German prosecutors of the Nazi Dr. Josef Mengele, who had died in 1979, by comparing DNA obtained from a femur bone of his exhumed skeleton, and DNA from his
widow and son, in a similar way to paternity testing.
[1] DNA profiling
DNA profiling based on highly variable minisatellites in the human genome was developed by a team of scientists led by Peter Gill at The Forensic Science Service in the
1990s. DNA fingerprinting was renamed as DNA profiling to stop confusion with fingerprints. DNA profiling focused on just a few of these highly variable minisatellites,
making the system more sensitive, more reproducible and amenable to computer databasing. With highly automated and sophisticated equipment, modern-day DNA profiling can
process hundreds of samples each day. This DNA profiling technique was the basis for the UK National DNA Database (NDNAD) launched in Britain in 1995. Ten minisatellites
plus a marker for sex determination are used with the current system developed for the NDNAD, giving a discrimination power of one in over a billion. Under British law,
anyone arrested has their DNA profile stored on a database (whether or not they are convicted), which now contains the DNA information of nearly five million people.
Jeffreys has opposed the current use of DNA profiling, where the government has access to that database, and has instead proposed a database of all people's DNA,
whose access would be controlled by an independent third party.
[2] What is DNA?
DNA, or deoxyribonucleic acid, is the hereditary material in humans and
almost all other organisms. Nearly every cell in a person's body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA),
but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).
The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion
bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and
maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.
DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule.
Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of
the double helix is somewhat like a ladder, with the base pairs forming the ladder's rungs and the sugar and phosphate molecules forming the vertical sidepieces of
the ladder.
An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the
sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.
[3] How does forensic identification work?
Any type of organism can be identified by examination of
DNA sequences unique to that species. Identifying individuals within a species is less precise at this time, although when DNA sequencing technologies progress farther,
direct comparison of very large DNA segments, and possibly even whole genomes, will become feasible and practical and will allow precise individual identification.
To identify individuals, forensic scientists scan 13 DNA regions, or loci, that vary from person to person and use the data to create a DNA profile of that individual
(sometimes called a DNA fingerprint). There is an extremely small chance that another person has the same DNA profile for a particular set of 13 regions.
Some Examples of DNA Uses for Forensic Identification:
• Identify potential suspects whose DNA may match evidence left at crime scenes
• Exonerate persons wrongly accused of crimes
• Identify crime and catastrophe victims
• Establish paternity and other family relationships
• Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers)
• Detect bacteria and other organisms that may pollute air, water, soil, and food
• Match organ donors with recipients in transplant programs
• Determine pedigree for seed or livestock breeds
• Authenticate consumables such as caviar and wine
[3] Is DNA effective in identifying persons?
DNA identification can be quite effective if used intelligently. Portions of the DNA sequence that vary the most among humans must be used; also, portions must be large enough to overcome the fact that human mating is not absolutely random.
Consider the scenario of a crime scene investigation . . .
Assume that type O blood is found at the crime scene. Type O occurs in about 45% of Americans. If investigators type only for ABO, finding that the "suspect" in a crime is type O really
doesn't reveal very much.
If, in addition to being type O, the suspect is a blond, and blond hair is found at the crime scene, you now have two bits of evidence to suggest who really did it. However, there
are a lot of Type O blonds out there.
If you find that the crime scene has footprints from a pair of Nike Air Jordans (with a distinctive tread design) and the suspect, in addition to being type O and blond, is also
wearing Air Jordans with the same tread design, you are much closer to linking the suspect with the crime scene.
In this way, by accumulating bits of linking evidence in a chain, where each bit by itself isn't very strong but the set of all of them together is very strong, you can argue
that your suspect really is the right person.
With DNA, the same kind of thinking is used; you can look for matches (based on sequence or on numbers of small repeating units of DNA sequence) at many different locations on
the person's genome; one or two (even three) aren't enough to be confident that the suspect is the right one, but thirteen sites are used. A match at all thirteen is rare
enough that you (or a prosecutor or a jury) can be very confident ("beyond a reasonable doubt") that the right person is accused.
See some recent articles about statistical analysis on this topic:
• NY Times Freakonomics Blog, Aug.19, 2008
• Los Angeles Times, July 20, 2008
[3] How is DNA typing done?
Only one-tenth of a single percent of DNA (about 3 million bases)
differs from one person to the next. Scientists can use these variable regions to generate a DNA profile of an individual, using samples from blood, bone, hair, and other body
tissues and products.
In criminal cases, this generally involves obtaining samples from crime-scene evidence and a suspect, extracting the DNA, and analyzing it for the presence of a set of specific
DNA regions (markers).
Scientists find the markers in a DNA sample by designing small pieces of DNA (probes) that will each seek out and bind to a complementary DNA sequence in the sample. A series
of probes bound to a DNA sample creates a distinctive pattern for an individual. Forensic scientists compare these DNA profiles to determine whether the suspect's sample matches
the evidence sample. A marker by itself usually is not unique to an individual; if, however, two DNA samples are alike at four or five regions, odds are great that the samples
are from the same person.
If the sample profiles don't match, the person did not contribute the DNA at the crime scene.
If the patterns match, the suspect may have contributed the evidence sample. While there is a chance that someone else has the same DNA profile for a particular probe set, the
odds are exceedingly slim. The question is, How small do the odds have to be when conviction of the guilty or acquittal of the innocent lies in the balance? Many judges consider
this a matter for a jury to take into consideration along with other evidence in the case. Experts point out that using DNA forensic technology is far superior to eyewitness
accounts, where the odds for correct identification are about 50:50.
The more probes used in DNA analysis, the greater the odds for a unique pattern and against a coincidental match, but each additional probe adds greatly to the time and expense
of testing. Four to six probes are recommended. Testing with several more probes will become routine, observed John Hicks (Alabama State Department of Forensic Services). He
predicted that DNA chip technology (in which thousands of short DNA sequences are embedded in a tiny chip) will enable much more rapid, inexpensive analyses using many more
probes and raising the odds against coincidental matches.
[3] What are
some of the DNA technologies used in forensic investigations?
Restriction Fragment Length Polymorphism (RFLP)
RFLP is a technique for analyzing the variable lengths of DNA fragments that result from digesting a DNA sample with a special kind of enzyme. This enzyme, a restriction
endonuclease, cuts DNA at a specific sequence pattern know as a restriction endonuclease recognition site. The presence or absence of certain recognition sites in a DNA
sample generates variable lengths of DNA fragments, which are separated using gel electrophoresis. They are then hybridized with DNA probes that bind to a complementary
DNA sequence in the sample.
RFLP was one of the first applications of DNA analysis to forensic investigation. With the development of newer, more efficient DNA-analysis techniques, RFLP is not used
as much as it once was because it requires relatively large amounts of DNA. In addition, samples degraded by environmental factors, such as dirt or mold, do not work well with RFLP.
PCR Analysis
Polymerase chain reaction (PCR) is used to make millions of exact copies of DNA from a biological sample. DNA amplification with PCR allows DNA analysis on biological samples
as small as a few skin cells. With RFLP, DNA samples would have to be about the size of a quarter. The ability of PCR to amplify such tiny quantities of DNA enables even highly
degraded samples to be analyzed. Great care, however, must be taken to prevent contamination with other biological materials during the identifying, collecting, and preserving
of a sample.
STR Analysis
Short tandem repeat (STR) technology is used to evaluate specific regions (loci) within nuclear DNA. Variability in STR regions can be used to distinguish one DNA profile
from another. The Federal Bureau of Investigation (FBI) uses a standard set of 13 specific STR regions for CODIS. CODIS is a software program that operates local, state,
and national databases of DNA profiles from convicted offenders, unsolved crime scene evidence, and missing persons. The odds that two individuals will have the same 13-loci
DNA profile is about one in a billion.
Mitochondrial DNA Analysis
Mitochondrial DNA analysis (mtDNA) can be used to examine the DNA from samples that cannot be analyzed by RFLP or STR. Nuclear DNA must be extracted from samples for use in RFLP,
PCR, and STR; however, mtDNA analysis uses DNA extracted from another cellular organelle called a mitochondrion. While older biological samples that lack nucleated cellular
material, such as hair, bones, and teeth, cannot be analyzed with STR and RFLP, they can be analyzed with mtDNA. In the investigation of cases that have gone unsolved for
many years, mtDNA is extremely valuable.
All mothers have the same mitochondrial DNA as their daughters. This is because the mitochondria of each new embryo comes from the mother's egg cell. The father's sperm
contributes only nuclear DNA. Comparing the mtDNA profile of unidentified remains with the profile of a potential maternal relative can be an important technique in
missing-person investigations.
Y-Chromosome Analysis
The Y chromosome is passed directly from father to son, so analysis of genetic markers on the Y chromosome is especially useful for tracing relationships among males or
for analyzing biological evidence involving multiple male contributors.
[3] Some Interesting
Uses of DNA Forensic Identification:
• Identifying September 11th Victims
Identifying the victims of the September 11, 2001, World Trade Center attack presented a unique forensic challenge because the number and identity of the victims were
unknown and many victims were represented only by bone and tissue fragments. At the time of the attack, no systems were in place for rapidly identifying victims in
disasters with more than 500 fatalities. The National Institutes of Justice assembled a panel of experts from the National Institutes of Health and other institutions
to develop processes to identify victims using DNA collected at the site. Panel members produced forms and kits needed to enable the medical examiner's office to
collect reference DNA from victims' previously stored medical specimens. These specimens were collected and entered into a database. The medical examiner's office
also received about 20,000 pieces of human remains from the World Trade Center site, and a database of the victims' DNA profiles was created. New information technology
infrastructure was developed for data transfer between the state police and medical examiner's office and to interconnect the databases and analytical tools used by
panel members. In 2005 the search was declared at an end because many of the unidentified remains were too small or too damaged to be identified by the DNA extraction
methods available at that time. Remains of only 1585, of the 2792 people known to have died had been identified. In 2007, the medical examiner's office reopened the
search after the Bode Technology Group developed a new methodology of DNA extraction that required much less sample material than previously necessary. The victim
DNA database and the new methods have allowed more victims to be identified, and further identifications will be possible as forensic DNA technology improves.
• The DNA Shoah Project
The DNA Shoah Project is a genetic database of people who lost family during the Holocaust. The database will serve to reunite families separated during wartime and
aid in identifying victims who remain buried anonymously throughout Europe.
• Disappeared Children in Argentina
Numerous people (known as "the Disappeared") were kidnapped and murdered in Argentina in the 1970s. Many were pregnant. Their children were taken at birth and, along
with other kidnapped children, were raised by their kidnappers. The grandparents of these children have been looking for them for many years. Read an article about a
DNA researcher who has been helping them.
• Tomb of the Unknowns
• Son of Louis XVI and Marie Antionette
PARIS, Apr 19, 2000 (Reuters) -- Scientists cracked one of the great mysteries of European history by using DNA tests to prove that the son of executed French King
Louis XVI and Marie-Antoinette died in prison as a child. Royalists have argued for 205 years over whether Louis-Charles de France perished in 1795 in a grim Paris
prison or managed to escape the clutches of the French Revolution. In December 1999, the presumed heart of the child king was removed from its resting place to enable
scientists to compare its DNA makeup with samples from living and dead members of the royal family -- including a lock of his mother Marie-Antoinette's hair.
• The Murdered Nicholas Romanov, the Last Czar of Russia, and His Family
• Peruvian Ice Maiden
The Ice Maiden was a 12-to-14-year old girl sacrificed by Inca priests 500 years ago to satisfy the mountain gods of the Inca people. She was discovered in 1995 by
climbers on Mt. Ampato in the Peruvian Andes. She is perhaps the best preserved mummy found in the Andes because she was in a frozen state. Analysis of the Ice Maiden's
DNA offers a wonderful opportunity for understanding her genetic origin. If we could extract mitochondrial DNA from the Ice Maiden's tissue and successfully amplify
and sequence it, then we could begin to trace her maternal line of descent and possibly locate past and current relatives.
• African Lemba Tribesmen
In southern Africa, a people known as the Lemba heed the call of the shofar. They have believed for generations that they are Jews, direct descendants of the biblical
patriarchs Abraham, Isaac, and Jacob. However unlikely the Lemba's claims may seem, modern science is finding ways to test them. The ever-growing understanding of
human genetics is revealing connections between peoples that have never been seen before.
• Super Bowl XXXIV Footballs and 2000 Summer Olympic Souvenirs
The NFL used DNA technology to tag all the Super Bowl XXXIV balls, ensuring their authenticity for years to come and helping to combat the growing epidemic of
sports memorabilia fraud. The footballs were marked with an invisible, yet permanent, strand of synthetic DNA. The DNA strand is unique and is verifiable any
time in the future using a specially calibrated laser.
A section of human genetic code taken from several unnamed Australian athletes was added to ink used to mark all official goods — everything from caps to socks — from
the 2000 Summer Olympic Games. The technology is used as a way to mark artwork or one-of-a-kind sports souvenirs.
• Migration Patterns
Evolutionarily stable mitochondrial DNA and Y chromosomes have allowed bioanthropologists to begin to trace human migration patterns around the world and identify family lineage
o See Genetic Anthropology, Ancestry, and Ancient Human Migrations
• Wine Heritage
Using DNA fingerprinting techniques akin to those used to solve crimes and settle paternity suits, scientists at the University of California, Davis, have discovered that 18 of
the world's most renowned grapevine varieties, or cultivars are close relatives. These include varieties long grown in northeastern France such as Chardonnay, the "king of whites,"
and reds such as Pinot and Gamay noir, are close relatives.
• Snowball the Cat
A woman was murdered in Prince Edward Island, Canada. Her estranged husband was implicated because a snowy white cat hair was found in a jacket near the scene of the crime,
and DNA fragments from the hair matched DNA fragments from Snowball, the cat belonging to the husband's parents. See M. Menotti-Raymond et al., "Pet cat hair
implicates murder suspect," Nature, 386, 774, 1997. Also see Holmes, Judy, Feline Forensics, Syracuse University Magazine, Summer 2001.
• Angiosperm Witness for the Prosecution
The first case in which a murderer was convicted on plant DNA evidence was described in the PBS TV series, 'Scientific American Frontiers.' A young woman was murdered in
Phoenix, Arizona, and a pager found at the scene of the crime led the police to a prime suspect. He admitted picking up the victim but claimed she had robbed him of his
wallet and pager. The forensic squad examined the suspect's pickup truck and collected pods later identified as the fruits of the palo verde tree (Cercidium spp.).
One detective went back to the murder scene and found several Palo Verde trees, one of which showed damage that could have been caused by a vehicle. The detective's
superior officer innocently suggested the possibility of linking the fruits and the tree by using DNA comparison, not realizing that this had never been done before.
Several researchers were contacted before a geneticist at the University of Arizona in Tucson agreed to take on the case. Of course, it was crucial to establish evidence
that would stand up in court on whether individual plants (especially Palo Verde trees) have unique patterns of DNA. A preliminary study on samples from different
trees at the murder scene and elsewhere quickly established that each Palo Verde tree is unique in its DNA pattern. It was then a simple matter to link the pods
from the suspect's truck to the damaged tree at the murder scene and obtain a conviction. [WNED-TV (PBS - Buffalo, N.Y.)]
Famous cases involving DNA evidence
Bibliography
[1] Wikipedia
[2] Genetics Home Reference
[3] Human Genome Project Information
Part 2 follows soon
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