Lecture 7


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Lecture 7

  1. 1. Lecture 7 BIOL L100 Indiana University Southeast David Partin, Instructor
  2. 2. Today’s Agenda <ul><li>Announcements/Questions </li></ul><ul><li>Lecture 7: Mendelian Genetics and beyond </li></ul><ul><li>Practice Punnett Squares </li></ul><ul><li>One Minute Paper </li></ul><ul><li>Lab </li></ul><ul><li>Introduce Case Study #1 </li></ul>
  3. 3. Chapter 11 <ul><li>Mendelian Genetics (and beyond) </li></ul>
  4. 4. <ul><li>Gregor Mendel: </li></ul><ul><li>Austrian monk </li></ul><ul><li>Scientist </li></ul><ul><li>Pea farmer </li></ul><ul><li>Snazzy dresser </li></ul>
  5. 5. Most traits are inherited independently. Mendel’s experiments refuted the “blending” concept of inheritance.
  6. 6. Genotype- Phenotype- Homozygous- Heterozygous-
  7. 7. Punnett Square Capital letters are always used to represent dominant traits. Dominant trait- Recessive trait-
  8. 8. Alleles -alternate forms of a gene. Locus -alleles can be found on homologous chromosomes at a particular location called a gene locus.
  9. 9. Let’s draw both parents’ chromosomes to make this concept clearer.
  10. 10. Phenotype of offspring can reveal genotype of parents.
  11. 11. Connection: Mendel’s Laws and Meiosis Instead of 1 trait at a time, let’s look at how 2 traits can be passed together.
  12. 12. Dihybrid cross- Could you draw the parents’ chromosomes? Homozygous dominant Homozygous recessive
  13. 14. Heterozygous for both traits Homozygous recessive
  14. 15. Let’s take a break… <ul><li>Thanks for your attention! </li></ul><ul><li>When we return: </li></ul><ul><ul><li>Human pedigrees </li></ul></ul><ul><ul><li>Beyond Mendelian Genetics </li></ul></ul>
  15. 16. 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-
  16. 17. Examples: Tay-Sachs Disease, Cystic Fibrosis, Phenylketonuria (PKU)
  17. 18. Huntington Disease and Neurofibromatosis, for example
  18. 19. Incomplete Dominance-
  19. 20. Co-Dominance- Multiple alleles-
  20. 21. Polygenic inheritance-
  21. 23. Environmental effects on genetics
  22. 24. Any questions?
  23. 25. Take a short break if you need one! <ul><li>What’s next? </li></ul><ul><li>Practice Punnett Squares </li></ul><ul><li>One-Minute Paper </li></ul><ul><li>Lab </li></ul><ul><li>Introduce Case Study #1 </li></ul>
  24. 26. Punnett Squares <ul><li>Let’s do some practice problems… </li></ul>
  25. 27. Overview of today’s lab <ul><li>In this exercise, you will observe and record the results of the offspring produced in a dihybrid heterozygous cross of two corn phenotypes. </li></ul><ul><li>The corn kernel phenotypes are: </li></ul><ul><ul><li>Purple & starchy (purple & nonwrinkled) </li></ul></ul><ul><ul><li>Purple & sweet (purple & wrinkled) </li></ul></ul><ul><ul><li>Yellow & starchy (yellow & nonwrinkled) </li></ul></ul><ul><ul><li>Yellow & sweet (yellow & wrinkled) </li></ul></ul><ul><li>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. </li></ul><ul><li>Record your results & answer the questions on pp55-56. </li></ul><ul><li>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… </li></ul>
  26. 28. Case Study #1 <ul><li>“ Sometimes it IS all in the Genes” </li></ul><ul><li>Mendelian genetics, Punnett squares </li></ul><ul><li>Cystic fibrosis: autosomal recessive disorder </li></ul>
  27. 29. Preparation for Lecture 8 <ul><li>Study today’s lecture materials (and Ch. 11 & 12), so that Lecture 8 will be more useful to you. </li></ul><ul><li>Read Ch. 13 </li></ul>