Eminem

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Who are Eminems parents? Why?
A B C
Eminem
D E F G
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Genetics

• The study of heredity

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• Remember alleles are different versions of the
  same ________.
• homozygous both alleles the same dd, DD
• heterozygous _______ are different Dd
• trait observed expression of the gene (Physical
  manifestation of information)

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Gregor Mendel

• Austrian monk
• Studied pea plants
• Crossed them
• Pea plants usually self-fertilize
• Took pollen from male part and put it on female
  part of another flower

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• Studied heredity the passage of traits from
  generation to generation
• Monitored the characteristics of pea plants to
  see how traits (physical characteristics) were
  passed
• Began with plants that are PURE for a trait
• Plants that always produce offspring with that
  trait
• i.e. Pure-breed dogs
• Offspring (children) of P1 generation ____
• Offspring of ____ generation ____

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• Discovered F1s from 2 pure breeds (P1) always
  the same!
• This suggested that one trait was DOMINANT over
  another! (or 1 trait was RECESSIVE)
• ___________ traits cover up the effects of
  _________ traits.

x means cross, or a mating of 2 individuals
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Appearances can be deceiving!

• Mendel found that one PHENOTYPE was dominant over
  another.
• PHENOTYPE physical appearance due to your genes
• The information used to make up this physical
  appearance is in your genes ___________

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F1 Crosses
Seed Shape
Flower Position
Seed Coat Color
Seed Color
Pod Color
Plant Height
Pod Shape
Round
Yellow
Gray
Smooth
Green
Axial
Tall
Wrinkled
Green
White
Constricted
Yellow
Terminal
Short
Round
Yellow
Gray
Smooth
Green
Axial
Tall
In the first generation of each experiment, how
do the characteristics of the offspring compare
to the parents characteristics?
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Mendels Principle of Dominance

• 2. Some alleles are

DOMINANT
recessive
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Allele Symbols

• Dominant allele ? capital letter
• Height ex T tall

• Recessive allele ? lowercase letter
• Height ex t short

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Traits exist because of 2 alleles

• Every trait has 2 _______ that determines its
  phenotype.
• AA or Aa or aa
• AA Homozygous Dominant
• Aa Heterozygous
• aa ___________ __________
• It is because of this, that the recessive trait
  can disappear in the F1 generation.

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Genotype vs. Phenotype
Question Can two organisms have the same
phenotype but have different genotypes? Explain.
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Punnet Squares

• Used to predict possible genotypes and phenotypes
  of a genetic cross
• What are possible combinations of these P1
  alleles? (remember, 2 alleles for each trait)
• Mom TT Dad TT
• Mom tt Dad tt
• Mom Tt Dad Tt
• Mom TT Dad Tt
• Mom tt Dad Tt

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Try this one out
Genotype Phenotype TT
Tall Tt ___
tt short What is the
phenotypic ratio?
These are called monohybrid crosses
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Punnet Practice

• Cross a green pea plant (bb) with a heterozygous
  yellow plant (Bb)
• Genotypic Ratio
• Phenotypic Ratio

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Test Cross

• Crossing 2 organisms, one of them a homozygous
  recessive individual, and looking at the
  phenotypes of the offspring to determine the
  other parent phenotype and/or genotype.
• Example problem
• A test cross between 2 pea plants gave offspring
  with a phenotypic ratio of 22 for plant height.
  What were the parents genotypes and phenotypes?

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Dihybrid crosses

• Crossing 2 different traits at the same time
  (like pea color and plant height)
• Example problem
• Cross a heterozygous yellow, short pea plant with
  a homozygous dominant yellow, homozygous dominant
  tall plant.

Yellow,tall Yellow,short Green,tall
Green,short
Phenotypic ratio ____________________