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Exploring Mendelian Genetics 11-3

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Exploring Mendelian Genetics 11-3 Independent Assortment Inheritance Patterns Beyond Simple Dominance Quick Review Allele: each letter (R or r) Dominant masks ... – PowerPoint PPT presentation

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Title: Exploring Mendelian Genetics 11-3


1
Exploring Mendelian Genetics11-3
  • Independent Assortment
  • Inheritance Patterns Beyond Simple Dominance

2
Quick Review
  • Allele each letter (R or r)
  • Dominant masks Recessive (Rr or rr)
  • Law of Dominance?
  • Homozygous RR/rr
  • Heterozygous Rr

3
Law of Independent Assortment
  • States that genes for different traits can
    segregate independently during meiosis
  • Gives many more genetic variations
  • MEANING If a pea plant is yellow and wrinkled lt
    RrYygt, both sets of alleles will separate
    independently (they work alone!)
  • An offspring can receive any combination of rs
    and ys

4
Dihybrid Crosses Used For Proof (pg 270/271)
5
Incomplete Dominance
  • Dominant and Recessive Blend in a heterozygous
    genotype
  • Ex Flower Color
  • Red (RR) Flower X White (rr) Flower PINK (Rr)
  • Can you think of other examples?

6
Co dominance
  • No recessive, Both traits expressed
  • Excoat color
  • Heterozygous
  • will both be capital
  • letters because
  • both dominant!

7
RRBlack, WWWhite, RWBlack and White Bunny
8
Other Ways To Show Genotypes
  • Use 2 different letters (all caps)
  • Ex BWblack and white bunny
  • Use apostrophes to show the other allele
  • Ex RR red RR white RRRoan
  • (Roan both)
  • Found in cows, horses, dogs, etc

9
Examples of Roan Animals(co-dominant coat color)
10
Multiple Alleles
  • Genes with 3 or more alleles
  • Ex Blood Typing
  • 3 alleles IA, IB, i
  • Give 4 possible phenotypes
  • A (IAIA, IAi)
  • B (IBIB, IBi)
  • AB (IAIB)
  • O (ii)

11
Heres How
  • AA A
  • Ai A
  • BB B
  • Bi B
  • AB AB
  • ii O

12
Polygenic Trait
  • Several Genes Influence a Trait
  • Ex Skin, Weight, Eye Color, Height
  • Most genes scattered along the same chromosome
  • What causes so many variations?

13
Traits Influenced by Environment
  • Phenotypes can change based on environment
  • Ex Hydrangea Color
  • Fur in mammals (color and thickness)
  • Height and weight in humans based nutrition
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