Text Readings in Lewis

Chapters 13 - 16 Review It Can't Be!, pgs 362 and 281 Using Human Genome Information, pgs 302-303 From Genetics to Biotechnology, pgs 334-335 Genes To The Rescue, pgs 326 and 345 New Routes to Plant Reproduction, pgs 558-559 Preembryos as Research Subjects, pgs 224-225 *DNA Fingerprinting: An Application of Understanding DNA Structure, pgs 313 & 314 *PCR: An Application of Understanding DNA Replication, pgs 320-321 *DNA Solves a Royal Mystery, pgs 308 and 323 * New for this lecture

For feedback, post possible answers and ideas in the folder"Text 'Review' and 'To Think About' Questions" in the Biology Chat Section of Web Crossing.

Objectives
After studying this material you should be able to:

1. Explain the effects of mutation and inheritance of DNA that provide the theoretical basis for the use of DNA fingerprinting, also called DNA profiling, as a tool for the identification of individuals or determination of the relationships of organisms.

2. Describe how the polymerase chain reaction (PCR) is used to make millions of copies of specific sequences of DNA. Discuss the significance of PCR in the location of specific DNA sequences in a small sample of tissue.

   PCR polymerase chain Reaction	Thermus aquaticus and taq polymerase
   Yellowstone National Park	high temperatures
   unzipping DNA	DNA primers for specific DNA sequences
   DNA nucleotides	binding or annealing of primers
   DNA replication	repetition

3. Explain how the maternal inheritance of mitochondria and the use of DNA fingerprinting make it possible to determine direct relationships between grandmothers and their grandchildren.

4. Describe how the techniques described in this and the previous two lectures are involved in the search for improved methods of gene therapy.

Web Resources:

• Understanding Gene Testing
  U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
  Public Health Service National Institutes of Health National Cancer Institute
  Accessed from Access Excellence a web site managed by Genentech, a biotechnology company in California

  These sites contain a wealth of information concerning genetics, DNA, and Biotechnology. I will include links to specific topics in the body of the outline for this lecture, however I invite you to explore on your own. There might be potential net surfer projects here.

• Access Excelence Graphics Gallery

• Principles Of Biotechnology North Central Regional Extension Publication Iowa State University - University Extension

• Biotechnology - The Future from Access Excellence

• The Washington Biotechnology Action Council This organization provides an alternative view of the potential benefits of biotechnology

• Enter a keyword or words to search (Access Excelence)

DNA Fingerprinting, also called DNA Profiling, makes use of segments of DNA that do not code for protein products, but do exhibit variability (caused by mutation) in the nucleotide base sequences from individulat to individual. When these segments of DNA are cut using restriction enzymes DNA fragments of various lengths are produced. If the DNA of an individual has mutations within restriction sites the DNA will not be cut at those sites and that individual's DNA fragments will be different in length from another's DNA fragments produced by the same restriction enzymes.

When the DNA fragments of an individual are separated by electrophoresis, transferred to a nylon membrane using the Southern blotting technique, and mixed with specific radioactive single-stranded DNA probes, a unique pattern of bands is produced when the membrane is autoradiographed. These bands can be used to identify that individual.

• See Lewis' Text: DNA Fingerprinting: An Application of Understanding DNA Structure, pgs 313 & 314

• DNA Finger Printing Case Study on Web Crossing

• Basics of DNA Fingerprinting By Kate Brinton and Kim-An Lieberman. This page was created as a class project at the University of Washington.

  These links provide more detailed information on DNA fingerprinting Especially:

  • Eric S. Lander - DNA on the Witness Stand and the 4 pages dealing with DNA fingerprinting.

  • Use of DNA in IdentificationA longer symposium by Dr. Eric S Lander - from Access Excellence

  • DNA Analysis and the O.J. Simpson Murder Case

PCR is a technique that uses a naturally occuring DNA polymerase enzyme to produce millions of copies of a specific sequence of DNA from a small sample of many different segments of DNA in a test tube, providing adequate quantities of DNA for analysis in a matter of hours. This technique makes it possible to generate the relatively large amounts of DNA needed for DNA profiling or for use in recombinant DNA processes from a very small sample of DNA. All it takes is a drop of blood from a crime scene or a tiny bit of flesh from the base of an elephant tusk.

• See Lewis' Text:
  • PCR: An Application of Understanding DNA Replication, pgs 320-321

  • Industrial Microbiology (Thermus aquaticus and PCR), pgs 452-454

• Extremophiles, from Scientific American This article discusses the organisms that live in extreme temperature and/or pressure conditions on earth. One of these extremophiles, Thermus aquaticus which lives in the hot springs of Yellowstone National Park, provides the enzyme, taq polymerase, needed to perform PCR. See the section of the article entitled "Not Too Hot to Handle".

• Polymerase Chain Reaction - Xeroxing DNA from Access Excellence

• Polymerase Chain Reaction (PCR) - A diagram from Access Excellence

The DNA fingerprinting applications noted in the section above made use of nuclear DNA from the chromosomes, but there are other cellular sources of DNA that can be used in DNA fingerprinting (DNA Profiling).

If one is working to determine plant identity or relationships, DNA from the chloroplasts is commonly used.

The cases described in the web links below made use of the anlysis of DNA from mitochondria to determine the identity of a woman's grandchildren. This is based on the understanding that a person's mitochondria are inherited solely from her/his mother.

The mitochondria of human egg cells are contained in the cytoplasm, but the mitochondria of human sperm are located at the base of the flagellum (tail). When a sperm manages to enter an egg cell during fertilization the flagellum is sloughed off and left outside the egg cell. The only mitochondria we inherit come from our mothers.

• Lewis' text: DNA Solves a Royal Mystery, pgs 308 and 323

• A Identification Applied to Human Rights

• The Grandmothers of the Placo de Mayo

• The Case of Heidi Llemos

• From Access Excellence
  • Gene Therapy - An Overview

  • Blazing a Genetic Trail in Medicine

Take me home.