Lab 18 DNA Murder Mystery

  • View
    68

  • Download
    0

Embed Size (px)

DESCRIPTION

Lab 18 DNA Murder Mystery. BY-102 Zach Nolen. DNA Fingerprinting. Is a technique used by forensic scientists to identify people based on their DNA profiles The key to DNA fingerprinting is Restriction Fragment Length Polymorphisms (RFLPs). When is it used?. Crime Investigations Rape - PowerPoint PPT Presentation

Text of Lab 18 DNA Murder Mystery

Lab 18 DNA Murder Mystery

Lab 18DNA Murder MysteryBY-102Zach NolenDNA FingerprintingIs a technique used by forensic scientists to identify people based on their DNA profilesThe key to DNA fingerprinting is Restriction Fragment Length Polymorphisms (RFLPs)

When is it used?Crime InvestigationsRapeViolent CrimesFamilial RelationshipsPaternity testsHow Specific Are RFLPs?Under normal circumstances, no other human has your exact complement of genes, unlessYou are an identical twinMurder CaseMurder CaseAfter going missing, Lynda Mann, a 15-year old schoolgirl was raped and murdered in the grounds of Carlton Hayes psychiatric hospital in Narborough, Leicestershire, in November 1983. Forensic examination of semen sample that it was a type found only in 10% of men, and was from someone with type A blood. However, the police did not find a suspect. In 1986, another 150year old schoolgirl, Dawn Ashworth, was similarly sexually assaulted and strangled in the nearby village of Enderby, and semen samples showed the same blood type.Suspect 1Richard Buckland (17 years old)Local with learning disabilitiesWorked at Carlton Hayes psychiatric hospitalSeen near murder scene of Dawn AshworthKnew detailed information regarding body of deceasedConfessed to the murder of Dawn Ashworth but not to the murder of Lynda MannSuspect 2Colin Pitchfork (27 years old)Local bakerPrevious convictions for flashingPaid someone to give a false semen sample to police during the investigation supposedly because of his prior convections.How can we find the culprit?DNA FingerprintingStepsExtract DNAAmplify DNACut DNASort DNADenature DNAHybridize DNAMake an X-RayExtract DNAWe performed an extraction last week using cold ethanol. Keep in mind that there are other ways to extract DNA.We will be going through these steps using the DNA sheet that you should have printed out.If you do not have the sheet, I have a few extras.Amplify DNAWe amplify DNA using Polymerase Chain Reaction (PCR). This allows us to increase the total amount of DNA that we haveFor our exercise, everyone having their copy of DNA will act as the amplificationCut DNATo cut DNA, Restriction enzymes are used.These enzymes cut DNA by recognizing specific sites in chains of DNAWe will act as restriction enzymes and cut our DNA at the indicated sites.Make sure that the sites match exactlyNeoSci 15 GG|CC 3 3 CC|GG 5NeoSci 25 GA|AG 33 CT|TC 5Sort DNAAfter the DNA is cut using restriction enzymes, it must be sorted using gel electrophoresisThis process separates DNA fragments based on sizeWe will cut paper DNA fragments out ant place them on our paper gelFill out p. 215 by placing dark lines at any location where a fragment would be present

Denature DNAAfter the DNA has been sorted, it must then be denatured using either heat or chemical.To denature our DNA, we will remove the yellow strips from the bottom of the fragments in our lanesHybridize DNAThis step binds a radioactive probe to the fragmented DNA so that it can be seen.We will cut out the T C C probes and place them under fragments with the corresponding letters A G GMake an X-RayThe process of taking an X-Ray of hybridized DNA is called AutoradiographyFill in lines on p. 214 to indicate fragments where hybridization has occurred.ResultsSuspect 2: Colin Pitchfork is the murder.Colin Pitchfork was the first person ever to convicted of murder based on DNA fingerprinting evidence.Paternity TestsReview QuestionsWhat is the key to DNA fingerprinting?What can DNA fingerprinting be used for? What do we use to cut DNA?How do we sort DNA?Before you leave labClean up your work stationBefore next labRead Lab 7 The Cardiovascular SystemDo Online PrelabComplete sections in lab manual for lab notebook check