Set up Cornell Notes on pg.

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• Set up Cornell Notes on pg.
• 75
• Topic 7.2 Patterns of Inheritance
• Essential Questions
• Why might polygenic traits vary more in phenotype
  than do single-gene traits?
• How is codominance the same as having no dominant
  and recessive relationship at all between 2
  alleles?

7.2 Patterns of Inheritance
2.1 Atoms, Ions, and Molecules

1. Why might polygenic traits vary more in phenotype
   than do single-gene traits?
2. How is codominance the same as having no dominant
   and recessive relationship at all between 2
   alleles?

KEY CONCEPT Phenotype is affected by many
different factors.
2
KEY CONCEPT Phenotype is affected by many
different factors.
3

• What are our possible outcomes for this
  combination of flower color?
• What if red nor white was dominant or recessive
  to one another?

4

• In incomplete dominance, neither allele is
  completely dominant nor completely recessive.
• They are a BLEND of each other
• Ex redwhite rose pink rose

BB RR
BR
5
B
B


BR
BR
R
BR
BR
R
Genotype Phenotype
BR
100 pink flowers
6
B R


BB Red rose
BR Pink rose
B
BR Pink rose
R
RR White rose
BB red RR white BR pink
Genotype
25 red flowers 50 pink flowers 25
white flowers
Phenotype
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• Codominant alleles will both be completely
  expressed.

• Codominant alleles are neither dominant nor
  recessive.

Ex multi-colored red and white rose
8
B
B


BR
BR
R
BR
BR
R
Genotype Phenotype
BR
100 red and white flowers
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• Polygenic traits are produced by two or more
  genes.
• Can produce a continuous range of colors
• Ex Skin color- 4 genes
• Eye color- at least 3 genes