1. Targets Describe Law of Segregation Identify Phenotype & Genotype
Probability
Monohybrid Cross Section
P1 generation and F1 generation

2. Law of Segregation is when allele pairs separate during formation and unite at fertilization

3. Allele - different forms of genes.
Most genes have two alleles
Dominant - trait we see
Example - Tall (T) - will be represented by a capital letter
Recessive - trait that will not be seen
Example - Short (t) - will be represented by a lowercase letter

4. Homozygous - same alleles for a trait (pure)
Examples - TT, tt, BB, bb, AA, aa
Heterozygous - different alleles for a trait
Example - Tt, Bb, Aa
Hybrids - offspring of parents that have different forms of a trait

5. Genotype (the letters we use) - the set of genes in our DNA which is responsible for a particular trait
Example: TT, Tt, tt
Responsible for determining eye color, hair color, height, how your voice sounds, certain diseases, certain behaviors, the size of a bird’s beak, the length of a fox’s tail, the color of stripes on a cat, the spots on a dog’s back, a person’s shoe size

6. Phenotype (the words we use) - the physical expression, or characteristics, of that trait.
Example: Green pea or Tall plant
Responsible for the actual visible characteristics of eye color, hair color, height, how your voice sounds, certain diseases, certain behaviors, the size of a bird’s beak, the length of a fox’s tail, the color of stripes on a cat, the spots on a dog’s back, a person’s shoe size

7.  Probability is used in genetics to determine the possibilities of offspring having a particular trait.
¼ = 25%
2/4 = 50%
¾ = 75%
4/4 = 100%

8. P1 Parental generation – is the first set of parents crossed
F1 filial generation - is the first filial generation of offspring different from their parental generation

9. Example 1 Round Pea Plant Dominant Heterozygous – Rr
Wrinkled Pea Plant
Recessive
Heterozygous - Rr

10. Punnett Square Parents: a heterozygous dominant round pea plant (P1)
a heterozygous recessive wrinkled pea plant (P1)
New offspring: 3 round plants and 1 wrinkled plant (F1)

11. Example 2 Homozygous - tt Dominant Homozygous– TT Recessive
Tall Pea Plant
Dominant
Homozygous– TT
Short Pea Plant
Recessive
Homozygous - tt

12. Punnett Square t t T T T T T t t Tt Tt Tt Tt Parents:
a homozygous dominant tall pea plant (P1)
a homozygous recessive short pea plant (P1)
New offspring: 4 tall pea plants (F1)

13. Example 3 Tall Pea Plant Dominant Homozygous– TT Short Pea Plant
Recessive
Heterozygous - Tt

14. Punnett Square Parents:
a homozygous dominant tall pea plant ____________ (P1)
a heterozygous recessive short pea plant _________ (P1)
New offspring:
__________Tall Plant (F1)
__________Short Plant (F1)
__________ Phenotype
__________ Genotype

15. Example 4
Punnett square with heterozygous (Aa) and homozygous recessive parents (aa)
If only one parent has a single copy of a dominant allele for a long hair
their children will have a 50% chance of inheriting the disorder and 50% chance of being entirely normal.

16. Example 5
If both parents are carriers of the recessive allele for a disorder, all of their children will face the following odds of inheriting it:
25% chance of having the recessive disorder
50% chance of being a healthy carrier
25% chance of being healthy and not have the recessive allele at all

17. Genotype (the letters we use) - the set of genes in our DNA which is responsible for a particular trait Example: TT, Tt, tt
Phenotype (the words we use) - the physical expression, or characteristics, of that trait. Example: Green pea or Tall plant
Homozygous - same alleles for a trait Examples - TT, tt, BB, bb, AA, aa
Heterozygous - different alleles for a trait Example - Tt, Bb, Aa
P1 Parental generation – is the first set of parents crossed
F1 filial generation - is the first filial generation of offspring different from their parental generation
Probability is used in genetics to determine the possibilities of offspring having a particular trait. ¼ = 25% 2/4 = 50% ¾ = 75% 4/4 = 100%