Lecture 7 BIOL L100 Indiana University Southeast David Partin, Instructor

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Lecture 7BIOL L100 Indiana University
SoutheastDavid Partin, Instructor
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Todays Agenda

• Announcements/Questions
• Lecture 7 Mendelian Genetics and beyond
• Practice Punnett Squares
• One Minute Paper
• Lab
• Introduce Case Study 1

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Chapter 11

• Mendelian Genetics (and beyond)

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• Gregor Mendel
• Austrian monk
• Scientist
• Pea farmer
• Snazzy dresser

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Most traits are inherited independently.
Mendels experiments refuted the blending
concept of inheritance.
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Genotype- Phenotype- Homozygous- Heterozygous-
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Punnett Square
Dominant trait- Recessive trait-
Capital letters are always used to represent
dominant traits.
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Alleles-alternate forms of a gene. Locus-alleles
can be found on homologous chromosomes at a
particular location called a gene locus.
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Lets draw both parents chromosomes to make this
concept clearer.
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Phenotype of offspring can reveal genotype of
parents.
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Connection Mendels Laws and Meiosis
Instead of 1 trait at a time, lets look at how 2
traits can be passed together.
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Homozygous dominant
Homozygous recessive
Dihybrid cross-
Could you draw the parents chromosomes?
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Homozygous recessive
Heterozygous for both traits
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Lets take a break

• Thanks for your attention!
• When we return
• Human pedigrees
• Beyond Mendelian Genetics

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KEY Square- Circle- Shaded- Unshaded- Horizontal
line- Vertical line-
Obviously, it wouldnt be ethical to do
test-crosses on humans! We record human genetic
information in a pedigree.
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Examples Tay-Sachs Disease, Cystic Fibrosis,
Phenylketonuria (PKU)
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Huntington Disease and Neurofibromatosis, for
example
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Incomplete Dominance-
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Multiple alleles-
Co-Dominance-
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Polygenic inheritance-
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Environmental effects on genetics
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Any questions?
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Take a short break if you need one!

• Whats next?
• Practice Punnett Squares
• One-Minute Paper
• Lab
• Introduce Case Study 1

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Punnett Squares

• Lets do some practice problems

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Overview of todays 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. Dont 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 wont be turned in or graded, but some
  questions on the exam may look similar

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Case Study 1

• Sometimes it IS all in the Genes
• Mendelian genetics, Punnett squares
• Cystic fibrosis autosomal recessive disorder

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Preparation for Lecture 8

• Study todays lecture materials (and Ch. 11
  12), so that Lecture 8 will be more useful to
  you.
• Read Ch. 13