Name ____________________________________________________ Per. ________

DIHYBRID CROSS WORKSHEET

Principle of independent assortments states __________________________________

________________________________________________________________________

In guinea pigs, black hair is dominant to white hair. Also, short hair is dominant to long hair. These letters represent the genotypes of the rabbits.

BB= black hair Bb= black hair Bb= white hair

LL- short hair Ll- short hair ll- long hair

What are the phenotypes (descriptions) of rabbits that have the following genotypes?

Bbll______________________________ bbLL______________________________

bbll______________________________ BbLl______________________________

F________________O________________I________________L________________

1. Cross the parents with the genotype

BbLl x BbLl

How many out of 16 have black long hair? ___

How many out of 16 have black short hair? ___

How many out of 16 have white short hair? ___

How many out of 16 have white long hair? ___

2. Rabbit fur color gray (G) is dominant to white (g). Black eyes (B) are dominant to red eyes (b). Cross a male rabbit GGbb to a female rabbit ggBb.

Parents: ______________x ______________

Out of 16 offsprings, how many would have…

Gray fur & black eyes ____

Gray fur & red eyes ____

White fur & black eyes ____

White fur & red eyes ____

3. Set up a punnett square for seed color and shape using the following information:

Dominant allele for green seeds= G Dominant allele for round seeds= R Recessive allele for yellow seeds= g Recessive allele for wrinkled seeds= r

Cross a heterozygous parent (GgRr) with a recessive yellow wrinkled seed.

Parents: ________________ x _________________

What is the probability of producing green round seeds? _______

What is the probability of producing green wrinkled seeds? ________

What is the probability of producing yellow round seeds? ________

What is the probability of producing yellow wrinkled seeds? _________

4. An aquatic arthropod called a Cyclops has antennae that are either smooth or barbed. The allele for barbs (B) is dominant over smooth (bb). In the same organism non-resistance to pesticides (N) is dominant over resistance to pesticides (nn). Make a “Key” to show all the possible genotypes and phenotypes of this organism.

Genotypes Phenotypes BBNN barbed & nonresistant ________ ________ ________ ________ ________ ________ ________ ________

5. A Cyclops that is resistant to presticides and has smooth antennae is cross with one that is homozygous dominant for both traits. Show the genotypes of the parents.

Parents: ______________x ______________

Out of 16 offsprings, how many would have…

Barbed antennae & resistant to pesticides _____

Barbed antennae & non-resistant to pesticides __

Smooth antennae & resistant to pesticides _____

Smooth antennae & non-resistant to pesticides__