Mendelian Genetics

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Class Topics
Title Biology 2/8/08
Objectives

• To prepare for Mendelian genetics.

• Mendelian Genetics
• Practice Problems
• Chapter 9 Quiz 1 Review
• Homework time
• Notes
• incomplete dominance
• Codominance
• Dihybrid crosses
• "The reward of a job well done, is to have done
  it."
• Ralph Waldo Emerson, 1844

Sunday, November 15, 2009 626 AM
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• If youre the first person to exit the classroom,
  please block open the door.
• If youre not willing to do this, dont be the
  first one out!

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Class Assignments
By When
What

• Chapter 9 Quiz 1 2/11/08
• Genetics Problems W.S. 2/12/08
• Due this class period
• Due next class period
• Due in the future

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Phenotype

• The physical appearance of a trait
• Tall or dwarf plants
• Round or wrinkled seeds
• Yellow or green seeds

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Mendels Cross

• Cross a purebreeding white flower with a
  purebreeding purple flower.
• P ____ x ____
• F1
• Pheno ___ Purple ___ White
• Geno ___ PP ___Pp ___pp
• F2 ____ x ____
• Pheno ___ Purple ___ White
• Geno ___ PP ___Pp ___pp

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Chapter 9 Quiz 1 Review

• Matching
• Alleles, Dominant, Gene, Genetics, Genotype,
  Heredity, Homozygous, Heterozygous, Hybrid,
  Independent assortment, Phenotype, Recessive,
  Segregation,Trait
• Mendels traits
• Mendels success
• Genetic symbols
• Mendels cross

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Practice problem

• Using the trait of flower position, cross a
  hybrid with a purebreeding terminal.
• P ___ x ___
• F1
• Pheno
• Geno

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Practice problem

• Tall is dominant over short cross a homozygous
  dominant with a heterozygous
• P ___ x ___
• F1
• Pheno
• Geno

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Math Labp. 165

• Calculating Mendels ratios
• Copy the table
• Calculate the ratio
• State the ratio in words and then as a fraction
• Answer the final question

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Incomplete dominance

• In some organisms neither allele is dominant
• Blending of traits
• Snapdragons - red, white, and pink
• P ___ x ___
• F1
• Pheno
• Geno

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From http//www.synapses.co.uk/genetics/codom.ht
ml
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Co-dominance

• Both traits are dominant and shown equally
• Roan cattle - both red hairs and white hairs
• 3 phenotypes - red, white, roan
• Erminette chickens - both black and white
  feathers
• 3 phenotypes - black, white, and black and white

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http//tidepool.st.usm.edu/crswr/codominance.html