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Genetics: An Introduction

Genetics: An Introduction. Biology 12. A little motivational video:. http:// www.youtube.com/watch?v=B_PQ8qYtUL0. What is Genetics?. The science that studies heredity Heredity is the passing of traits from parents to offspring. Joke of the day:. Variation:.

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Genetics: An Introduction

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  1. Genetics: An Introduction Biology 12

  2. A little motivational video: http://www.youtube.com/watch?v=B_PQ8qYtUL0

  3. What is Genetics? • The science that studies heredity • Heredity is the passing of traits from parents to offspring

  4. Joke of the day:

  5. Variation: • Genetic variation describes naturally occurring genetic differences among individuals of the same species • Why? • Recombination of chromosomes that occurs during sexual reproduction (called independent assortment) • Crossing over during meiosis

  6. Some vocabulary: • Genes • Humans have ~21,500 • Chemical instructions for building proteins • Locus/loci:specific location on a chromosome • Diploid cells contain two copies of each gene on pairs of homologous chromosomes • Allele: each version of a gene

  7. Video: ABC News: All in the family: Mixed race twins http://abcnews.go.com/Health/twins-white-black-born-biracial-parents-stirs-issues/story?id=12984334

  8. The color of skin is genetically very complicated! • Skin color comes from the pigment melanin • Produced by melanocytes in skin cells • More than 100 genes directly or indirectly influence amount of melanin in an individual’s skin • Lead to many variations in skin color

  9. History of Genetics • People have known about inheritance for a long time. • children resemble their parents • domestication of animals and plants, selective breeding for good characteristics • Sumerian horse breeding records • Egyptian data palm breeding

  10. Mid 1800’s Discoveries • Major events in the mid-1800’s led directly to the development of modern genetics. • 1859: Charles Darwin publishes The Origin of Species, which describes the theory of evolution by natural selection. This theory requires heredity to work. • 1866: Gregor Mendel publishes Experiments in Plant Hybridization, which lays out the basic theory of genetics. It is widely ignored until 1900.

  11. History of Genetics: • Pioneer of Genetics: Gregor Mendel • Born in 1822 in Czechoslovakia. • Became a monk at a monastery in 1843. • Taught biology and had interests in statistics. • Also studied at the University of Vienna

  12. Major Events in the 20th Century • 1900: rediscovery of Mendel’s work by Robert Correns, Hugo de Vries, and Erich von Tschermak . • 1904: Gregory Bateson discovers linkage between genes. Also coins the word “genetics”. • 1910: Thomas Hunt Morgan proves that genes are located on the chromosomes (using Drosophila). • 1944: Oswald Avery, Colin MacLeod and Maclyn McCarty show that DNA can transform bacteria, demonstrating that DNA is the hereditary material. • 1953: James Watson and Francis Crick determine the structure of the DNA molecule, which leads directly to knowledge of how it replicates • 1966: Marshall Nirenberg solves the genetic code, showing that 3 DNA bases code for one amino acid. • 1972: Stanley Cohen and Herbert Boyer combine DNA from two different species in vitro, then transform it into bacterial cells: first DNA cloning. • 2001: Sequence of the entire human genome is announced.

  13. To do : Read pages 130 and 131. Read Mendel biography articles and answer the questions at the bottom based on both readings!

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