DNA Fingerprinting Project

Person·s unique identifier  Scientific technique of taking  a cell and comparing  it 95.5% of DNA is the same, it is the 4.5% that isn·t the same

Can tell if samples

are from

The same person Related person Non-related person

Get a Certain Probability Match

What is DNA?

Chemical Structure Chromosomes

Double Helix Base Strands of DNA are connected

Research Began in the late 70·s early 80·s Alec Jeffreys DNA sequence not different but the number of times it is repeated September 10th, 1984 Sir Alec Jeffreys

Stage 1:

Cells are broken down to release DNA

If only a small amount of DNA is available it can be amplified by using a polymerase chain reaction (PCR)

Stage 2: The

DNA is then cut into little fragments using restriction enzymes. Each restriction enzyme cuts DNA at a specific base sequence.

For example:

This

creates thousands of restriction fragments of all different sizes because the base sequences being cut may be far apart (long fragment) or close together (short fragment).

Stage 3: Fragments are then separated by size using a process called gel electrophoresis. The

DNA is then injected into wells and an electric current is applied along the opposite sides of the gel.

DNA is negatively charged so it is attracted to the positive end of the gel. The

shorter DNA fragments move faster than the longer fragments so they travel deeper into the gel.

A radioactive material is added to combines with the DNA fragments that makes them show up on a nylon sheet. This

makes a photographic copy of the DNA bands.

Stage 4: The

pattern of the fragment distribution is then analysed and compared.

DNA fingerprinting was introduced into the courts in the US in 1988. DNA typing was considered flawed from the beginning because the companies had no track record within the forensic field. Several early cases had poorly defined procedures and useless interpretations of the evidence. 

(Lander and Budowle)

´CSI

Belief Systemµ

If the DNA of the suspect and the DNA evidence appear sufficiently similar the samples are declared a match.

If any of the fragments are separated by more than three standard deviations of the measurement, it is declared a non-match and the donor is released from the suspect list (Roeder).

Nucleix; an Israeli group of scientists revealed through their published work in a forensics journal that they successfully took blood and saliva from one individual and was able to replace it with different DNA samples from another donor.

How? They

extracted the white blood cells (containing the DNA) and left the red blood cells, and added amplified DNA from another donor«

They

sent the sample they created to a wellknown forensics lab in the United States and when it was analyzed as a normal sample They

were unaware and unable to tell it had been modified in any way

Nucleix is now promoting a test designed to tell the difference between real and faked/modified DNA samples. 

(Arnold)

Privacy: Increases genetic discrimination by:     

Government

Insurers Employers Schools Banks & others

Practicality: Backlog of over half a million DNA samples wait to be entered into he CODIS system

Who

is chosen for sampling?

United States - Each state legislature independently decides whether DNA can be sampled for arrestees or convicts. Katie·s Bill ² New Mexico, 2006  Previous Law: Only required DNA from convicted felons  New Law: Requires police to take DNA samples from suspects in most felony arrests  Fourth Amendment violation? y

y

Civil liberties advocates says violations against unreasonable search and seizure Stressed law could be abused to justify arrests made on less than probable cause just to obtain DNA evidence.

As of September 2007: All 50 states: Require convicted sex offenders to submit DNA. 44 states: Require convicted felons to submit DNA 9 states: Require DNA samples from those convicted of certain misdemeanors 11 states: Laws authorizing arrestee DNA sampling 

Alaska, Arizona, California, Kansas, Louisiana, Minnesota, New Mexico, N. Dakota, Tennessee, Texas, & Virginia

Major crimes are often committed by people with other offenses. DNA bank makes it easier to find suspects. Innocent people are being incarcerated for crimes they didn·t commit. DNA being taken at the time of the arrest may have proven them innocent by now. DNA banking from arrestees· results in financial savings in: investigation, prosecution, and incarceration.

Arrestees found innocent of crimes & the retention of their DNA raises ethical & social issues. People may be identified as matches or partial matches to DNA found at crime scenes if they were there earlier or have similar DNA profile to actual criminal.

Sensitive genetic information can be obtained from DNA samples. Police & other officials would have access to the people·s DNA without their consent. Seen as intrusion of personal privacy and a violation of civil liberties.

Even the most secure database has a chance of being compromised.

Human Genome Project Information. 16 June 2009. 21 February 2011 . U.S. Citizenship and Immigration Services. 13 January 2011. 21 February 2011 . Arnold, Paul. "Who Invented DNA Fingerprinting?" 22 July 2010. BrightHub. 22 February 2011 . Lieberman, Kate Brinton and Kim-An. "Basics of DNA Fingerprinting." 1994. Protist Biology Washington. 22 February 2011 . McGuigan ,Brendan. " What Is DNA Fingerprinting?" 15 February 2009. Wisegeek. 24 February 2011 < http://www.wisegeek.com/what-is-dnafingerprinting.htm>.