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Manipulating DNA: Understanding DNA Fragmentation

This lesson explores the concept of cutting DNA and the use of restriction enzymes in biotechnology. Students will learn about gel electrophoresis and how to interpret a restriction map.

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Manipulating DNA: Understanding DNA Fragmentation

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  1. 9.1 Manipulating DNA 2.1 Atoms, Ions, and Molecules • Set up Cornell Notes on pg. 15 • Topic: 9.1 Manipulating DNA • Essential Question: • Suppose you cut DNA. You know that you should find four DNA fragments on a gel, but only three appear, and one fragment is very large. Explain what happened? • Suppose you cut DNA. You know that you should find four DNA fragments on a gel, but only three appear, and one fragment is very large. Explain what happened? KEY CONCEPT Biotechnology relies on cutting DNA at specific places

  2. P.14

  3. Points to Ponder (Top of p. 14) A natural disaster strikes. Families are separated. How can they be reunited? If a body is found and the person cannot be identified by looks, how can we identify them? What types of identifiers do we have?

  4. A natural disaster strikes. Families are separated. How can they be reunited? If a body is found and the person cannot be identified by looks, how can we identify them? What types of identifiers do we have? • DNA- skin, sperm, saliva, blood • Fingerprinting • Teeth

  5. Unidentified body found after the sinking of the RMS Titanicknown as “The Unknown Child” NO. 4 - MALE - ESTIMATED AGE, 2 - HAIR, FAIR. CLOTHING - Grey coat with fur on collar and cuffs; brown serge frock; petticoat; flannel garment; pink woolen singlet; brown shoes and stockings. No marks whatever. Possibly third-class.[3]

  6. The sailors aboard the Mackay-Bennett, who were very upset by the discovery of the unknown boy's body, paid for a monument, and he was buried on 4 May 1912 with a copper pendant placed in his coffin by recovery sailors that read "Our Babe."

  7. His body, identified as that of a child around two years old, was initially believed to be that of either a two-year-old Swedish boy, Gösta Pålsson; a two-year-old Irish boy, Eugene Rice,  or Eino Viljami Panula, a 13-month old Finnish baby • However, with improved DNA testing available in 2007, Canadian researchers at Lakehead University in Thunder Bay tested the child's HVS1, a type of mitochondrial DNA molecule, and it did not match the Panula family.

  8. Finally identified in 2007 using DNA evidence • DNA extracted from the exhumed remains and DNA provided by a surviving maternal relative helped positively match the remains to Sidney Leslie Goodwin (1910-1912), and the reidentification was announced on 30 July 2007 • The Goodwins and their 6 children were third class passengers and all perished

  9. KEY CONCEPT Biotechnology relies on cutting DNA at specific places. Baby 81 was rescued after the 2004 Indian Ocean tsunami. He was reunited with his parents by using DNA fingerprinting technology

  10. Biotechnology allows us to • Produce transgenic organisms • Clone • Study diseases and evolution • Produce medical treatments for people with illnesses

  11. DNA cannot be picked up and rearranged by hand • Therefore, scientists must be able to work with DNA without being able to see it, or handle it directly

  12. Scientists use several techniques to manipulate DNA. • Chemicals, computers, and bacteria are used to work with DNA. • Scientists use these tools in genetics research and biotechnology.

  13. Restriction enzymes act as “scissors” by cutting DNA • allow scientists to more easily study and manipulate genes • cut DNA at a specific nucleotide sequence called a restriction site Restriction enzyme DNA

  14. Different restriction enzymes cut DNA in different ways. • each enzyme has a different restriction site

  15. some cut straight across and leave “blunt ends” • some make staggered cuts and leave “sticky ends” Sticky ends

  16. Between what nucleotides does this restriction enzyme cut between? T and C or C and T

  17. Restriction Enzymes (Middle of p. 14) Restriction enzyme: cuts between T and A ATTACGACCTAGGACG 1. How many fragments are produced? 2. Are all the fragments the same length? 3. Please organize the fragments from biggest to smallest. 4. How many nucleotides in each segment when organized?

  18. Restriction enzyme: cuts between T and A ATTACGACCTAGGACG How many fragments are produced? 3 Are all the fragments the same length? No Please organize the fragments from biggest to smallest. ACGACCT/AGGACG/ATT How many nucleotides in each segment when organized? 7, 6, 3

  19. Restriction Enzyme Video 2m39s

  20. After DNA has been cut, several different things can be done with it: • The gene can be studied • The gene can be placed in another organism • But first, the DNA fragments have to be separated from one another • Sorted according to their size

  21. Gel electrophoresis is used to separate DNA fragments by size. • A DNA sample is cut with restriction enzymes • Electrical current pulls DNA fragments through a gel

  22. Smaller fragments move faster and travel farther than larger fragments • Fragments of different sizes appear as bands on the gel

  23. A restriction map shows the lengths of DNA fragments between restriction sites. • only indicate size, not DNA sequence • useful in genetic engineering • used to study mutations

  24. Restriction Enzymes (Middle of p. 14) Restriction enzyme: cuts between T and A ATTACGACCTAGGACG You organized the fragments from biggest to smallest. ACGACCT (7) AGGACG (6) ATT (3)

  25. - Grab 3 colors. Please organize the fragments from biggest to smallest on this restriction map. ACGACCT (7) AGGACG (6) ATT (3) 10 9 8 7 6 5 4 3 2 1 0 - - - Draw and complete this restriction map on the bottom of pg. 14 +

  26. “Who Ate the Cheese?” Warm-Up • Please complete the warm-up by yourself • Books open to 266-267 • 5 mins

  27. Who Ate the Cheese?Practice Gel Electrophoresis-Restriction Enzyme Lab Objective: You will examine crime evidence and model the process of gel electrophoresis and DNA fingerprinting to identify the person who ate the Queen’s cheese. • Read the Royal Incident Report • You are looking for the sequence CCGG GG CC • The restriction enzyme always cuts between the C /G • All cuts will leave blunt ends • Count the number of base pairs in each fragment of DNA • Record the # on the bottom of each DNA fragment • Make a restriction map to identify who, if anyone, is guilty of eating the queen’s cheese

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