Dihybrid Crosses

Dihybrid crosses1. Crosses involving 2 different traits. Example: Height & color

2. 1st generation produced all dominant traitsexample: parents TTYY x ttyy

(tall,yellow) (short, green)

produced offspring TtYy

(tall, yellow)

Parents:TTYY X ttyyTo figure out what goes on

the top and sides of the boxes.

TTYY

TY TY TY TY

TY TY TY TY ty

ty

ty

ty

TY TY TY TYty

ty

ty

ty

TtYy TtYy TtYy TtYy

TtYy TtYy TtYy TtYy

TtYy TtYy TtYy TtYy

TtYy TtYy TtYy TtYy

All offspring have the genotype TtYy and their phenotype is Tall, and Yellow

3. 2nd generation produced a mix of traits.

Parents:TtYy X TtYyTo figure out what goes on

the top and sides of the boxes.

TtYy

TY Ty tY ty

TY Ty tY tyTY

Ty

tY

ty

In Dihybrid crosses when you cross a heterozygous with a heterozygous you get a 9:3:3:1 ratio

d/d d/r r/d r/r

Genotypes: Phenotypes:

T= Tall Y= yellow

t= short y= green