1. Start-up for Tuesday, November 6, 2012
For each genotype, indicate whether it is heterozygous or homozygous:
For each genotype, determine the phenotype:
Purple flowers are dominant to white flowers:
For each phenotype, list a different genotype (use the letter of the dominant trait)
Tall plants are dominant to short plants Ee
B) GG
C) HH
D) Jj
E) pp PP
B) Pp
C) pp
Tall
C) Short

2. Mendelelian Genetics Chapter 11 Section 2 Objective:
Summarize Mendel’s Law of Segregation
Define monohybrid and dihybrid crosses
List the purpose and steps of completing a Punnett Square
Use punnett squares to predict genotypic and phenotypic expectations of single trait crosses

3. Obj. A) Summarize Mendels’ Law of Segregation – Focus on the F2
During the formation of gametes (eggs or sperm), the two alleles for a trait separate from each other.
Each gamete carries a single copy of each gene
Alleles for a trait are then "recombined" at fertilization, one from each parent producing the genotype for the traits of the offspring

4. Cross 2 Pure Plants TT x tt Results in all Hybrids Tt
A) Summarize Mendel’s Law of Segregation
Cross 2 Pure Plants TT x tt
Results in all Hybrids Tt
Cross 2 Hybrids get 3 Tall & 1 Short TT, Tt, tt
Because short reappeared in F2, he knew the allele for shortness had not disappeared, the F1 still carried it. F1 cross proves segregation.

5. Obj B) Define monohybrid and dihybrid crosses
Heredity - passing of traits
Genetics - study of heredity
Monohybrid cross - cross of a single hybrid trait, proves segregation law e.g. flower color
Dihybrid cross - cross of two hybrid traits, proves independent assortment e.g. flower color & plant height

6. Obj C)List the purpose and steps of completing a Punnett Square
Used to predict genetic cross outcomes
Gives a mathematical percentage for the offspring of a genetic cross = probability (expectation)

7. C) List the purpose and steps of completing a Punnett Square
ID the parent genotypes. Use letter of dominant trait.
Make the grid.
Place alleles of one parent along the top. Place alleles of other parent on the left side. This will split them.

8. 4. Fill in the grid like multiplication tables.
C) List the purpose and steps of completing a Punnett Square
4. Fill in the grid like multiplication tables.
Write the genotypes.
Use the Law of Dominance to determine phenotypes. Any capital letter = dominant trait appearance.
What is the only way to receive a recessive trait?

9. r r Rr Rr R R Rr Rr P1 Single Trait Cross Trait: Seed Shape
Obj. D) Use punnett squares to predict genotypic and phenotypic expectations of single trait crosses
P1 Single Trait Cross
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Homozygous Round seeds x Wrinkled seeds
RR x rr r r
Genotype Ratio:
100% Rr
Phenotype Ratio:
100% Round Rr Rr R R Rr Rr

10. R r RR Rr R r Rr rr F1 Monohybrid Cross Trait: Seed Shape
Obj. D) Use punnett squares to predict genotypic and phenotypic expectations of single trait crosses
F1 Monohybrid Cross
Trait: Seed Shape
Alleles: R – Round r – Wrinkled
Cross: Heterozygous seeds x Heterozygous seeds
Rr x Rr
Genotype:
25% RR, 50% Rr, 25% rr
Phenotype:
75% Round & 25% wrinkled
G.Ratio: 1:2:1
P.Ratio: 3:1 R r RR Rr R r Rr rr

11. P p Pp pp p p Pp pp Single Trait Practice Trait: Flower color
Obj. D) Use punnett squares to predict genotypic and phenotypic expectations of single trait crosses
Single Trait Practice
Trait: Flower color
Alleles: P – Purple p – White
Cross: White flowers x Heterozygous flowers
pp x Pp
Genotype:
50% Pp, 50% pp
Phenotype:
50% Purple, 50% White
Genotypic Ratio: 1:1
Phenotypic Ratio: 1:1 P p Pp pp p p Pp pp

12. Summary of Single Trait Crosses
Inheritable factors or genes are responsible for all heritable characteristics
Phenotype is based on Genotype
Each trait is based on two alleles, one from the mother and the other from the father
True-breeding individuals are homozygous (both alleles) are the same

13. Single Trait Practice Understanding Check Trait: Flower Height
Alleles: T – Tall t – short
Cross: Homozygous tall x Heterozygous plant x
Genotype Percentages:
Phenotype Percentages: