DNA Profiling LOs All pupils will: Recall the uses of DNA profiling. Most pupils will: Describe the method used to prepare a DNA profile. Some pupils will: Discuss the benefits of genetic profiling Skills: Communication, Problem Solving, WWO,

DNA is the single most important molecule in living cells

DNA are large molecules – You have about 9 MILLION KILOMETRES of DNA in your body

If you were to write down the codes for all the chemicals in your DNA it would fill about 200 phone books – about 3 billion letters

Around 99.1% of our genes or instructions are in common with the chimpanzee, which is our closest relative on earth

About 50 percent of human DNA is the same as the DNA found in bananas

DNA can store 10 gigabytes of information per cm DNA can store 10 gigabytes of information per cm. It is the most efficient storage system known to humans

However, the red blood cells have no DNA ! In the past, people thought that heredity was passed on through our blood – However, the red blood cells have no DNA !

DNA Profiling

DNA Profiling 1987 – Forensic scientist first used DNA profiling (genetic profiling) to solve a rape case The chemical structure of everyone's DNA is the same - the only difference is the order of the base pairs and every person has a different sequence.

DNA fingerprinting uses differences in DNA sequences to identify a specific individual. http://www.teachers.tv/videos/chemistry-in-forensics (11.40mins onwards)

Uses of DNA Fingerprinting 1. To determine a child’s paternity 2. To determine a familial connection 3. In criminal cases

How it works Only 0.1% of DNA differs from one person to the next. These differences are used to generate a DNA profile (from blood, bone, hair, or other body tissues) Enzymes are used to cut out specific sequences of DNA. Sequences are arranged in order of length using electrophoresis. They are labelled so that they show up when photographed.

DNA fingerprint Forensic comparison Which sample matches the blood stain? Sample A Sample B

Activity 1 Suppose the following are DNA samples of a couple who plan on having children. Give a possible DNA coding for two of their children. Mum Dad 1 2

Mum Dad 1 2 Mum Dad 1 2 Mum Dad 1 2 Mum Dad 1 2 Mum Dad 1 2 Mum Dad 1 2

Activity 2 Here are six different DNA tests. Suppose these DNA tests are of a couple who are married and their possible children. Which of the kids belong to both parents? Which of the kids belong to only the mother? Which of the kids belong to only the father? Which of the kids belong to neither parent?

Mum Dad 1 2 3 4

Mum Dad 1 2 3 4 Mum Dad 1 2 3 4 Mum Dad 1 2 3 4 Mum Dad 1 2 3 4

Gene Ownership – A National Database Britain has the largest DNA database of its citizens in the world. It holds details of over 4 million people – 5.2% of the UK population These include people who have been found guilty of a crime as well as those suspected of a crime but eventually cleared. Should there be a database?

Activity In groups think of as many arguments in favour of having a National database of DNA profiles and arguments against.

Arguments in favour Each person's DNA is unique so, DNA evidence collected from a crime scene can implicate or eliminate a suspect (like fingerprints) It also can analyse unidentified remains through comparisons with DNA from relatives When evidence from one crime scenes are compared, there may be a link to the same perpetrator, so helping to solve crimes If biological evidence from crime scenes is collected and stored properly, forensically valuable DNA, that may be decades old, could help solve an unsolved crime

Arguments against It is possible for an innocent person’s DNA to be planted at a crime scene An innocent person’s DNA may also be at a crime scene even though they weren’t involved in the crime High cost to maintain and develop the database It invades our right to privacy. The data might get into the hands of  commercial companies such as insurance, loan and employers.  If it were used to identify that you had a genetic risk for a serious disease, could you find yourself refused life insurance, a loan, or even a job? http://www.bbc.co.uk/learningzone/clips/dna-database-legal-or-illegal/8463.html

HSW Question Explain what is meant by ‘genetic profiling’, including its uses and the advantages and disadvantages associated with it. (6 Marks)

Answer…. Genetic profiling is where DNA is analysed to show a DNA ‘pattern’ That is specific to an individual DNA is cut into smaller pieces and separated by electrophoresis Pattern is compared to other samples Uses (any two): Paternity, criminal cases, familial connections Advantages (any one): Matching parents to children, genetic screening, providing evidence for criminal cases Disadvantages: (any one): Insurance rejections, not 100% accurate, invasion of privacy, affect chances of finding a job,

Keywords Specific DNA Profiles, Electrophoresis, Genetics Criminal Paternity Analysed

DNA – True or False? http://www.teachers.tv/videos/dna