DNA Forensics How DNA is used Ethical Issues By : Daniel DiCenzo
What is DNA? DNA - Deoxyribonucleic acid DNA is the blueprint for the design of our bodies Consists of certain base pairs that form specific sequences These sequences can code for specific amino acids These amino acids combine to form proteins The proteins together make our entire body Everyone’s DNA is unique DNA holds all of the information needed to make living things
What is DNA used to do? Code for amino acids in our bodies Act as a bar code that identifies who we are (DNA Fingerprint) DNA can be analyzed and compared to other DNA Comparing DNA can be used for many purposes To match and analyze people’s DNA, scientists must perform special tests
There are many ways to process DNA Polymerase Chain Reaction (PCR) Restriction Fragment Length Polymorphism (RFLP) Short Tandem Repeat (STR) Mitochondrial DNA (mtDNA) –DNA is taken from mitochondrion instead of nucleus What Are These Tests
Polymerase Chain Reaction To put it simply PCR’s are used to amplify a certain piece of DNA The initial piece of DNA is separated into two strands RNA primer is attached at specific spot on DNA DNA polymerase adds base pairs to both single stranded DNA The product is two identical pieces of double stranded DNA This process is repeated many times to achieve a large amount of DNA The amount of DNA produced after every cycle however increases exponentially This process allows a large amount of DNA to be produced from only a minute sample collected http://campus.queens.edu/faculty/jannr/Genetics/images/dnatech/ FG12_11cPCR2.JPG http://campus.queens.edu/faculty/jannr/Genetics/images/dnatech/ FG12_11cPCR2.JPG
Restriction Fragment Length Polymorphism DNA is cut at specific points into fragments These fragments are then put in a gel Via “gel electrophoresis” the DNA fragments travel across the gel and stop at specific distances DNA can be compared to other DNA run through this same method This process however requires a large amount of DNA sample http://www.ars.usda.gov/pandp/docs.htm?docid=11828
Short Tandem Repeat Example of a tandem repeat TAAGCTAAGCTAAGCTAAGC In this tandem repeat – TAAGC is repeated four times Every person’s DNA contains these tandem reapeats These are inherited from your mother and your father These are used in identification because they are very unique in individuals Scientists analyze 13 loci in our DNA, this prevents any doubt that someone else shares these same genes If only 2 loci are analyzed the probability that someone else shares those genes are much higher which is not effective in identifying people using DNA
What are these fingerprints used for? DNA fingerprinting has many uses DNA fingerprinting has the ability to: Prove someone is guilty/innocent of a crime Instantly find the culprit if they are in a DNA database Identify unknown bodies (old or new) Determine who the father of a baby is (Paternity Test) Find an organ match for a person Catch poachers hunting and selling the meat of endangered animals
Ethical Issues DNA identification Act (1998) –Forces all those in Canada who have been convicted of a certain crime to be entered into the National DNA Databank (NDDB) This is also the case in the U.S. –In 1998, all 50 states used their DNA databank, known as the National DNA Index System (NDIS) Having to be forced to provide DNA is a violation of human rights, even if you are a criminal Many believe in the future, everyone’s DNA will be on file All of our most valuable secrets are exposed Many believe this is an invasion of privacy Our DNA can predict how we will die, do we want that information?
Genetic Discrimination DNA holds secret to almost every weakness you have By allowing Insurance companies, employers, schools or banks access to any illness or flaw that you will, may or already have, you can be denied instantly Government can learn anything about you without your consent Those with “Good” DNA will be given better opportunities and success than those with “Bad” DNA This will lead to a new discrimination, not by race or religion, but by your DNA
Is DNA fingerprinting Reliable? People have come to believe that DNA evidence is indisputable in courtrooms (Too much faith in DNA) Human error is always a factor –Contamination of evidence –Labs are too pressured by police to give them the evidence they want to close the case With more strict regulations on the quality of labs and technological advances, human error will be greatly reduced Planting of evidence is a new problem –This always leaves doubt into the reliability of DNA evidence Must look for probable cause in a case and not rely solely on DNA evidence
DNA Databanks There are approximately 200 000 people in the Canadian National DNA Databank To this date there have been 10 000 offender hits because of this system In the U.S., 6.5 million people have been entered into their national DNA databank This databank is the largest in the world and has participated in over 77 000 investigations
http://www.nddb-bndg.org/stats_e.htm Taken from NDDB statistics page
Taken from NDDB annual report for 2006/2007 http://www.nddb-bndg.org/an_report_e.htm
Conclusion DNA holds all of the secrets of our bodies There are many ways that DNA can be used to identify and learn about other people It is an effective tool in crime solving The use of DNA databanks has caused major concern over the civil rights of convicted felons and possibly in the future, the civil rights of everyone If people’s DNA is exposed, there is concern for our privacy being violated
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