Gregor Mendel & Punnett Squares
Upcoming SlideShare
Loading in...5
×
 

Gregor Mendel & Punnett Squares

on

  • 21,051 views

 

Statistics

Views

Total Views
21,051
Views on SlideShare
20,992
Embed Views
59

Actions

Likes
1
Downloads
222
Comments
0

4 Embeds 59

http://www.slideshare.net 47
http://acker.pbwiki.com 8
http://wildfire.gigya.com 3
http://my.sycamoreschools.org 1

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Gregor Mendel & Punnett Squares Gregor Mendel & Punnett Squares Presentation Transcript

  • 11.1-11.2 Gregor Mendel &Punnett Squares Pages 262 - 266 PD -old
  • Goal 1 Describe how Mendel Studied inheritance in peas
    • Austrian Monk 1800’s
    • Taught High School
    • Managed monastery gardens
    • Pea plant observations
    • True-breeding plants
      • Self pollination = offspring identical to parents
    • Cross pollination used to study inheritance
      • Tall plant x short plant
      • Green seeds x yellow seeds
  • Goal 2 Summarize Mendel’s conclusions about inheritance
    • Results of Mendel’s experiment
      • Cross pollination of true breeding parents (P)
      • Offspring (F1) only show one trait
      • No “blending” of traits
    Tall plant x short plant = all tall plants P P F1
    • Mendel’s 1 st conclusions about inheritance
      • Inheritance determined by factors passed from one generation to the next
      • Each trait determined by one gene that occurs in two different forms ( alleles )
      • Trait of height located on one gene as either short or tall alleles
  • Goal 3 Explain the principle of dominance
    • He tried again with F1 generation
      • Cross pollination of F1 offspring
      • ¾ F2 offspring show one trait ¼ F2 show “hidden” trait
    F1 x F1 = F2 Tall plant x Tall plant = 3/4 tall plants ¼ short plants
  • Creative commons Image credit: Madprime
    • Principle of dominance states:
    • some alleles are dominant and others are recessive
      • If dominant allele present, it will be expressed
      • Recessive alleles only expressed if NO dominant allele present
  • Goal 4 Describe what happens to alleles during segregation in meiosis
    • Alleles separate during meiosis
    • Alleles segregate into one allele per gamete
    • Two types of gametes can be produced
    • Alleles pair up randomly when gametes unite during fertilization
    • Example on the board…
  • Goal 5 Use Punnett Squares to: determine genotypic and phenotypic ratios of a cross to Predict outcomes
    • Phenotype = the expressed physical trait
      • What can be seen (brown hair)
      • Dependent on genotype
    • Genotype = the alleles of a genetic code
      • Genetic code (one maternal, one paternal)
        • Homozygous = alleles are the same (BB or bb)
        • Heterozygous = alleles are different (Bb)
    • Recessive phenotype
      • Genotype MUST be homozygous recessive
      • Genotype bb expresses phenotype blond hair
    • Dominant phenotype
      • Genotype may be homozygous dominant
        • BB expresses brown hair
      • Genotype may be heterozygous
        • Bb also expresses brown hair
    • Genotypes are used to create Punnett Squares and compare possible combinations of gametes
    • Parent 1 gamete possibilities
    • Parent 2 gamete possibilities
    Possible Combination Possible Combination Possible Combination Possible Combination
  • B b b B Parent 1 : homozygous dominant Parent 2 : homozygous recessive Bb Bb Bb Bb
  • B b B b Parent 1 : heterozygous Parent 2 : heterozygous bb Bb BB Bb
  • B b B b Genotypic ratio of offspring 1BB : 2Bb : 1bb Phenotypic ratio of offspring 3 brown hair : 1 blond hair (75% chance) (25% chance) bb Blond hair Bb Brown hair BB Brown hair Bb Brown hair
  • ? ? ? ? Parent 1 : heterozygous (Bb) Parent 2 : homozygous recessive (??) ?? ?? ?? ??
  • B b b b Parent 1 : heterozygous (Bb) Parent 2 : homozygous recessive ( bb ) bb Bb Bb bb
  • B b b b bb Bb Bb bb Genotypic ratio of offspring ?? : ?? Phenotypic ratio of offspring ?? : ??
  • B b b b bb Bb Bb bb Genotypic ratio of offspring 2Bb : 2bb Phenotypic ratio of offspring 2 brown hair : 2 blond hair (50% chance) (50% chance)
    • Thanks to the following people who have generously shared images on Flickr creative commons:
    • Unertlkm… pea plant
    • Z e n… butterfly and pea bloom