Lecture 7
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Lecture 7






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Lecture 7 Lecture 7 Presentation Transcript

  • Lecture 7 BIOL L100 Indiana University Southeast David Partin, Instructor
  • Today’s Agenda
    • Announcements/Questions
    • Lecture 7: Mendelian Genetics and beyond
    • Practice Punnett Squares
    • One Minute Paper
    • Lab
    • Introduce Case Study #1
  • Chapter 11
    • Mendelian Genetics (and beyond)
    • Gregor Mendel:
    • Austrian monk
    • Scientist
    • Pea farmer
    • Snazzy dresser
  • Most traits are inherited independently. Mendel’s experiments refuted the “blending” concept of inheritance.
  • Genotype- Phenotype- Homozygous- Heterozygous-
  • Punnett Square Capital letters are always used to represent dominant traits. Dominant trait- Recessive trait-
  • Alleles -alternate forms of a gene. Locus -alleles can be found on homologous chromosomes at a particular location called a gene locus.
  • Let’s draw both parents’ chromosomes to make this concept clearer.
  • Phenotype of offspring can reveal genotype of parents.
  • Connection: Mendel’s Laws and Meiosis Instead of 1 trait at a time, let’s look at how 2 traits can be passed together.
  • Dihybrid cross- Could you draw the parents’ chromosomes? Homozygous dominant Homozygous recessive
  • Heterozygous for both traits Homozygous recessive
  • Let’s take a break…
    • Thanks for your attention!
    • When we return:
      • Human pedigrees
      • Beyond Mendelian Genetics
  • Obviously, it wouldn’t be ethical to do ‘test-crosses’ on humans! We record human genetic information in a pedigree . KEY Square- Circle- Shaded- Unshaded- Horizontal line- Vertical line-
  • Examples: Tay-Sachs Disease, Cystic Fibrosis, Phenylketonuria (PKU)
  • Huntington Disease and Neurofibromatosis, for example
  • Incomplete Dominance-
  • Co-Dominance- Multiple alleles-
  • Polygenic inheritance-
  • Environmental effects on genetics
  • Any questions?
  • Take a short break if you need one!
    • What’s next?
    • Practice Punnett Squares
    • One-Minute Paper
    • Lab
    • Introduce Case Study #1
  • Punnett Squares
    • Let’s do some practice problems…
  • Overview of today’s lab
    • In this exercise, you will observe and record the results of the offspring produced in a dihybrid heterozygous cross of two corn phenotypes.
    • The corn kernel phenotypes are:
      • Purple & starchy (purple & nonwrinkled)
      • Purple & sweet (purple & wrinkled)
      • Yellow & starchy (yellow & nonwrinkled)
      • Yellow & sweet (yellow & wrinkled)
    • Each team will count 3 ears of corn & record the total number of each type of kernel. Don’t remove the kernels. Use pins to mark the counted rows.
    • Record your results & answer the questions on pp55-56.
    • It could be useful to work through some of the questions at the end of Ch11 (pp201-202) and the “Practice Problems” found throughout the chapter. They won’t be turned in or graded, but some questions on the exam may look similar…
  • Case Study #1
    • “ Sometimes it IS all in the Genes”
    • Mendelian genetics, Punnett squares
    • Cystic fibrosis: autosomal recessive disorder
  • Preparation for Lecture 8
    • Study today’s lecture materials (and Ch. 11 & 12), so that Lecture 8 will be more useful to you.
    • Read Ch. 13