Tuesday 1/27

• Notes on 6.5
• Practice Doing Punnett Squares
• Homework: Read 6.5, 6.6

Good job everyone who demonstrated Punnett Squares today!

Punnett Square:

• Grid system for predicting all possible genotypes resulting from a cross.
  Axes: the possible gametesof each parent.
  Boxes: show thepossible genotypesof the offspring.

Monohybrid cross: involves one trait.(Mono=one, hybrid=combination)

• Homozygous dominant x Homozygous recessive
  Offspring: all heterozygous, all dominant
  
• Heterozygous x Heterozygous
  Genotypes: 1:2:1
  1 homozygous dominant: 2 heterozygous: 1 homozygous recessive
  Phenotypes: 3:1 dominant:recessive
  
• Heterozygous x Homozygous Recessive:
  Genotypes: 1:1, heterozygous : homozygous recessive
  Phenotypes: 1:1, dominant : recessive

Dihybrid cross: two traits.

•Mendel’s dihybrid crosses with heterozygous plants yielded a 9:3:3:1 phenotypic ratio.