1. 5.2- Studying Genetic Crosses
SBI 3U1- Ferrari

2. Punnett Squares
Punnett Square- A grid used to illustrate all possible genotypes and phenotypes of offspring from genetic crosses
Shows probability
Each square represents a 25% chance of occurrence for that trait

3. This is a monohybrid cross
Using Punnett Squares
This is a monohybrid cross
Possible F1 outcomes from a cross between two heterozygous parents.
The phenotype ratio is 3:1 for flower colour (purple to white)

4. Test Crosses
A cross between an individual of unknown genotype and homozygous recessive for that trait.
Analyzing the phenotype should provide insight into the unknown genotype.

5. Mendel’s Dihybrid Crosses
He crossed yellow, round seeds with green, wrinkled seeds
YYRR x yyrr
All F1 generation displayed both dominant traits- yellow and round

7. The Law of Independent Assortment
Mendel found a 9:3:3:1 ratio for every dihybrid cross he performed.
This law states that the alleles for one gene segregate or assort independently of the alleles for other genes during gamete formation.

8. The Chromosome Theory of Inheritance
By early 1900s scientists finally began to see the link between meiosis & inheritance
Walter Sutton ( 1902) proposed that genes located on chromosomes and this provides the basis for the segregation and independent assortment of alleles.

9. Homework 1) Please read and review 5.2 ( Pgs.208-217)
2) Punnett Square Practice Problems & Worksheets