California DNA

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 about 10 DNA regions 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 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

Is DNA effective in identifying persons?

DNA identification can be quite effective if used intelligently. That means that those portions of the DNA sequence that vary the most between humans must be used; also, large enough portions must be used to overcome the fact that human mating is not absolutely random.
Consider the scenario of an crime scene investigation...
Assume that type O blood is found at the crime scene. Type O occurs in about 45 % of Americans. If investigators only type for ABO, then finding that the "suspect" in a crime is type O really doesn't tell you very much.
If, in addition to being type O, the suspect is a blond, and blond hair is found at the crime scene, then you now have two bits of evidence to suggest that your suspect 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, then 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 a number of different locations on the person's genome; one or two (even three) isn't enough to be confident that the suspect is the right one, but 4 (sometimes 5) are used and a match at all 5 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. [answer provided by Daniel Drell of the U.S. DOE Human Genome Program]

How does forensic identification work?

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

Is DNA effective in identifying persons?

DNA identification can be quite effective if used intelligently. That means that those portions of the DNA sequence that vary the most between humans must be used; also, large enough portions must be used to overcome the fact that human mating is not absolutely random.
Consider the scenario of an crime scene investigation...
Assume that type O blood is found at the crime scene. Type O occurs in about 45 % of Americans. If investigators only type for ABO, then finding that the "suspect" in a crime is type O really doesn't tell you very much.
If, in addition to being type O, the suspect is a blond, and blond hair is found at the crime scene, then you now have two bits of evidence to suggest that your suspect 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, then 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 a number of different locations on the person's genome; one or two (even three) isn't enough to be confident that the suspect is the right one, but 4 (sometimes 5) are used and a match at all 5 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.
[answer provided by Daniel Drell of the U.S. DOE Human Genome Program]

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, it means that 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 they 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. (See "What Are the Odds?" section in the article "".) Testing with several more probes will become routine, observed John Hicks (Alabama State Department of Forensic Services). He predicted that, within the next 3 to 5 years, DNA chip technology (in which thousands of short DNA sequences are embedded in a tiny chip) will enable much more rapid, inexpensive analysis using many more probes, and raising the odds against coincidental matches.

Some Interesting Uses of DNA Forensic Identification

Kennewick Man has been discovered in the Pacific Northwest. His ancient remains have caused problems because of competing claims for the remains by Native American groups, public officials, and scientists. Bones found in the United States that predate the arrival of Europeans to the Americas are by law considered Native American, but the bones of Kennewick Man show characteristics different from Native Americans of that time period. DNA testing will be used to determine if Kennewick Man's DNA is similar to that of other Native Americans.
Numerous people (known as "the Disappeared") were kidnapped and murdered in Argentina in the 1970s. Many were pregnant. Their children were taken at birth, along with other young kidnapped children, and were raised by their kidnappers. The grandparents of these children are now looking for them. Read an about a DNA researcher who is helping them.
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 as a child in prison. 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 make-up with samples from living and dead members of the royal family -- including a lock of his mother Marie-Antoinette's hair.
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 present relatives.
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 a way to test them. The ever-growing understanding of human genetics is revealing connections between peoples that have never been seen before.

The NFL used DNA technology to tag all of 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 lineages.
Snowball the Cat
A woman was murdered in Prince Edward Island, Canada. 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. M. Menotti-Raymond et al., "Pet cat hair implicates murder suspect," Nature, 386: 774, 1997.
Angiosperm Witness for the Prosecution
For the first time a murderer has been convicted on DNA evidence obtained from a plant. The case 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 the 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 was 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.), January 19, 1994]

DNA Forensics Databases

National DNA Databank: CODIS
The Combined DNA Index System, CODIS, blends computer and DNA technologies into a tool for fighting violent crime. The current version of CODIS uses two indexes to generate investigative leads in crimes where biological evidence is recovered from the crime scene. The Convicted Offender index contains DNA profiles of individuals convicted of felony sex offenses (and other violent crimes). The Forensic index contains DNA profiles developed from crime scene evidence. CODIS utilizes computer software to automatically search these indexes for matching DNA profiles. Law enforcement agencies at federal, state, and local levels take DNA from biological evidence (e.g., blood and saliva) gathered in crimes that have no suspect and compare it to the DNA in the profiles stored in the CODIS systems. If a match is made between a sample and a stored profile, CODIS can identify the perpetrator.
This technology is authorized by the DNA Identification Act of 1994. All 50 states have laws requiring that DNA profiles of certain offenders be sent to CODIS. The database contains about 250,000 DNA profiles, with a 600,000 sample backlog awaiting processing.
Some individual states are considering expanding DNA databanking beyond CODIS. Louisiana has a law that went into effect in 1999 to collect DNA samples from all arrestees. New York and North Carolina are considering this also. Attorney General Janet Reno charged the to make recommendations on collecting DNA from all arrestees. These recommendations are available in the publications and (September 1999).

What types of DNA testing can California DNA accommodate?

CRIMINAL PATERNITY: California DNA's Lab has the distinction, of having the highest appellate acceptance for an RFLP DNA criminal paternity. Our Lab has years of experience performing these cases and typically provide reports so convincing that further testimony is unnecessary.
BODY IDENTIFICATION: This can involve direct comparison of tissues and other samples, and often requires the performance of "reverse paternity" calculations. California DNA's Lab has a track record with the unusual and sub-optimal samples often encountered under these circumstances is among the best.
DNA DATABANKING: California DNA's Lab has profiles under contract on more than 25,000 individuals that are currently in law enforcement data banks, including the FBI's National DNA Index System. We are capable of performing this work by both of the FBI acceptable platforms and are currently implementing robotic systems to improve the efficiency of these procedures.
NO SUSPECT CASE WORK : We contract with public sector crime laboratories to develop DNA profiles on evidence, primarily from sexual assaults, for whom law enforcement officials do not have viable suspects.