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Understanding DNA Technology: Extraction, Sequencing, and Genetic Engineering

This overview delves into the key methods and techniques in DNA technology, highlighting DNA extraction via chemical treatments and spooling. It explores the significance of restriction enzymes for DNA cutting and recombinant DNA formation. The electrophoresis technique is explained for fragment separation, while DNA sequencing processes are unraveled, showcasing the Polymerase Chain Reaction (PCR) for amplifying DNA. Insights from the Human Genome Project illustrate the broader implications of genetic engineering, including benefits in medicine, agriculture, and biotechnology.

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Understanding DNA Technology: Extraction, Sequencing, and Genetic Engineering

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Presentation Transcript

  1. DNA Technology

  2. DNA Extraction • Chemical treatments cause cells and nuclei to burst • The DNA is inherently sticky, and can be pulled out of the mixture • This is called “spooling” DNA

  3. “Spooled” DNA

  4. Genetic Engineering • Manipulating a set of genetic changes on an organisms DNA Double Helix by Nancy Werlin

  5. Cutting DNA • Restriction enzymes -cut DNA at specific sequences • Enzymes recognize 4-6 nucleotides and cut both strands of DNA ex: EcoR1, Bam1 …. • Recombinant DNA– DNA from two sources combined to produce a single DNA molecule

  6. Restriction Enzymes • Useful to divide DNA into manageable fragments

  7. Electrophoresis • DNA sequences can be separated based on size and charge • The phosphate groups are negatively charged • DNA is placed in a gel and electricity is run through

  8. Electrophoresis • Negative DNA moves toward the positively charged end of gel plate • Smaller fragments move farther and faster

  9. Electrophoresis

  10. What would it mean if there were the same amount of nucleotides in each DNA fragment? • Where else have we seen different sizes of DNA displayed?

  11. Karyotypes 

  12. Steps in DNA Sequencing • Many copies of a single strand of DNA are placed in a test tube • DNA polymerase is added • A mixture of nucleotides is added some of which have been treated w/ radioactive phosphorous dye • Each base (A,T,C,G) has a different color dye

  13. Steps in DNA Sequencing • By chance, some dyed nucleotides & some untreated strands are added • Dye molecules are large and stop the chain from growing

  14. DNA Sequencing • The result is DNA fragments of multiple sizes with colors that can be identified A,G,C, T

  15. DNA Sequencing • After the gel separates the resulting fragments by size, we 'read' the sequence from bottom to top.

  16. Copying DNA • Polymerase Chain Reaction • Also called PCR • A method of making many copies of a piece of DNA

  17. Steps in Copying DNA • A DNA molecule is placed in a small test tube • DNA polymerasethat can work at high temps is added

  18. Steps in Copying DNA • The DNA is heatedto separate the two strands • Primers, short pieces of DNA complementary to the ends of the molecule to be copied, are added

  19. Copying DNA • The tube is cooled, and DNA polymerase adds new bases to the separated strands

  20. PCR Large amounts of DNA can be made from a small starting sample

  21. DNA Fingerprinting • Process that identifies an individuals DNA pattern for their genes, and “junk” repeats between genes. • Exons – code for proteins • Introns – spacers

  22. using specific restriction enzymes to cut DNA at points representing the targeted tandem repeat sequences. • FBI looks at 13 specific repeats to compare between people

  23. DNA Fingerprint

  24. Cloning • Clone- a member of a group of genetically identical cells grown from a single cell • May be produced by asexual reproduction (mitosis)

  25. Cloning organisms • A body cell from one organism and an egg cell from another are fused • The resulting cell divides like a normal embryo

  26. 2 types • Reproductive cloning- Dolly • Therapeutic cloning- Make tissues or organs that are genetically identical to the donor

  27. Cloning “Dolly”

  28. Ethics of Cloning • Should we clone organisms? • Should we use clones for “spare parts”?? • Will scientists try to design “perfect” people?? • Who should control the use and design of a humans??

  29. Human Genome Project

  30. Human Genome Project • Started in 1990 • Research effort to sequence all of our DNA (46 chromosomes) • Over 3.3 billion nucleotides • Mapping every gene location (loci) • Conducted by scientists around the world

  31. HGP Insights • Only 2% of human genome codes for proteins (exons) • Other 98% (introns) are non-coding • Only about 20,000 to 25,000 genes (expected 100,000) • Proteome – organism’s complete set of proteins • About 8 million single nucleotide polymorphisms (SNP) – places where humans differ by a single nucleotide • About ½ of genome comes from transposons (pieces of DNA that move to different locations on chromosomes)

  32. Benefits of Human Genome Project • Improvements in medical prevention of disease, gene therapies, diagnosis techniques … • Production of useful protein products for use in medicine, agriculture, bioremediation and pharmaceutical industries. • Improved bioinformatics – using computers to help in DNA sequencing …

  33. Benefits of Genetic Engineering

  34. Biotechnology - • The use of gene science to create new products from plants and animals

  35. BiotechnologyProvides: • Improved food products • Medical advances – • (gene therapy and genetic screening) • An enhanced environment

  36. Herbicide Resistant Crops • Soybeans: Roundup Ready • Corn: Roundup Ready, Liberty Link • Cotton: BXN, Roundup Ready • Canola: Liberty Link, Roundup Ready + CP4EPSPS = Roundup gene Ready

  37. Biotechnology Breakthroughs • Insulin (1982) • First commercial biotech product • Reliable, inexpensive source of insulin • Rice • Enriched with beta-carotene and iron • Bananas • Containing edible hepatitis vaccine

  38. Biotechnology Breakthroughs • Potatoes with higher solid content • Garlic that lowers cholesterol • Fruits and vegetables that reduce risks of cancer and heart disease

  39. Environmental Benefits • Reduced pesticide use • Lower energy requirements • Cleaner water • Less soil erosion

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