crosses involving more than one gene dihybrid and polyhybrid crosses

Crosses Involving more than one gene

Crosses Involving more than one gene

Dihybrid and Polyhybrid Crosses

Dihybrid and Polyhybrid Crosses

Dihybrid Experiments

• Mendel also did experiments which tracked more than one gene.

• This is called a dihybrid cross

Law of Independent Assortment

• Each pairs of alleles separates independently of each other during gamete formation.

• What does this mean?

A Dihybrid Cross

• In pea plants, seeds can be round (R)or wrinkled (r). They can also be yellow (Y) or green (y). If two plants that are hybrid for each trait are crossed. What is the expected phenotypic ratio

Another Dihybrid Cross

• In pea plants, seeds can be round (R)or wrinkled (r). They can also be yellow (Y) or green (y). If a plant that is hybrid for seed shape but has green seeds is crossed with a plant that hybrid for all traits, what is the probability the plants – Will show all dominant traits– Have yellow-wrinkled seeds– Have green-round seeds

A TriHybrid Cross

• In pea plants, seeds can be round (R)or wrinkled (r). They can also be yellow (Y) or green (y).Pea plants can also have axial (A) or terminal flowers (a).

If two plants that are hybrid for all three traits what is the probability they will have plants that have wrinkled- yellow seeds with axial flowers.