I’m working on a biology exercise and need guidance to help me understand better.Activity 1: Preparation of Forensic Samples For this lab exercise, it will be your job as part of Cuyamaca’s Forensics Investigation Team to determine if there is sufficient evidence to charge one of the police department’s suspects with murder. The first parts of the procedure for a have already been completed by another part of the Cuyamaca forensics team. It will be your responsibility to run the final gel electrophoresis analysis to determine whether the sample from any of the suspects matches the blood sample found at the crime scene.
The following samples and standards are available to be tested: Standard: A HindIII DNA digest to be used as the size standard CS: This is the sample from the crime scene. S1: Suspect 1: Dr. Pete Moss S2: Suspect 2: Dr. Forest Moss S3: Suspect 3: Mr. Bud Wieser S4: This is a blood sample from the victim, Dr. Dinah Soares Each of the crime scene, suspect and the victim samples has already been prepared for analysis by the Cuyamaca Forensics Investigation Team using the following procedure:
1) Each blood sample was amplified using PCR (Polymerase Chain Reaction) to obtain sufficient DNA for forensic analysis.
2) Ten microliters of each of the five samples was added to a clean tube and the tubes were labeled according to the list shown above.
3) To each tube, 10 µl of an EcoR1/Pst1 restriction enzyme mix was added. All of the tubes were then incubated at 37oC for 45 minutes.
4) The tubes were allowed to cool to room temperature, and 5 µl of loading dye was added to each tube. These samples have now been delivered to you to complete the analysis of the DNA by agarose gel electrophoresis. It will be your responsibility to set up and run the gel, and then to analyze the results in order to determine whether if any of the three suspect’s DNA matches the DNA found on the broken window at the crime scene.
Activity 2: Gel Electrophoresis of Forensic Samples Preparation of Electrophoresis Gel The electrophoresis equipment you will use to separate the DNA fragments into patterns that can be compared is based on new technology that is somewhat different from the example you saw in the online demonstration. The agarose gel is already prepared for you to use, and also contains the ethidium bromide in the gel. This means that as soon as the gel has been run you will be able to view the results by placing the gel on an ultraviolet (UV) illumination box. In this lab exercise you will use the E-Gel® electrophoresis system. It consists of a precast agarose gel which already contains ethidium bromide (EtBr) and the EGel®PowerBase
Question 1: Do you see any of the band patterns in the different lanes that appear to match each other? Which lanes? Question 2: Do any of the suspect samples appear to have recognition sites at the same location as the DNA from the crime scene? Question 3: Based on the analyses you have done, do any of the suspect samples of DNA seem to be from the same individual as the DNA from the crime scene? Describe the scientific evidence that supports your conclusion.
Activity 4: Summary of Data Analysis In this activity, you will be summarizing your findings to the police department in order to determine whether they have sufficient evidence for an arrest in the case. On the Skill Check worksheet, write a summary of 3-4 paragraphs of your evidence, and who (if anyone) it points to as the alleged murderer. Be sure to discus
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