1. Dihybrid Cross Di= 2 Cross with 2 different traits
You need 16 boxes in your punnett square

2. Example of a Dihybrid Cross
A new breed of hamster was discovered recently in near Sugar Creek. In hamsters blond hair color is dominant to white. These cute little creatures also have a peculiar trait. Research has shown that some have dominant alleles for dancing (D).

3. Example of a Dihybrid Cross
Scientists have decided to cross two heterozygous blonde-haired dancing hamsters, whose mothers did not dance.
What are the genotypes for these hamsters?

4. Example of a Dihybrid Cross
What are the possible genotypes of their offspring?
We need a punnett square divided into 8 boxes to find out.
Draw the punnett square.

5. b D d B BD Bd bD bd BbDd x BbDd
Find each possible combination from the 2 alleles.
**Use FOIL** b D d B
BD Bd
bD bd

6. Example of a Dihybrid Cross
Put the letter combinations from the alleles of the 1st parent above the boxes. BD Bd bD bd

7. Example of a Dihybrid Cross
Now put the letter combinations from the alleles of the 2nd parent beside the boxes (on the left side). BD Bd bD bd BD Bd bD bd

8. Example of a Dihybrid Cross
Now just follow the same steps as you would in a monohybrid cross.
This time there are just 4 letters instead of 2. BD Bd bD bd BD Bd bD bd

9. Results BBDD BBDd BbDD BbDd BBdd Bbdd bbDD bbDd bbdd BD Bd bD bd BD Bd

10. Questions 1BBDD:2BBDd:2BbDD:1BBdd:4BbDd: 2Bbdd:1bbDD :2bbDd:1bbdd
PHENOTYPES:
Blonde Dancing
Blonde Non-Dancing
White Dancing
White Non-Dancing

11. Results BBDD BBDd BbDD BbDd BBdd Bbdd bbDD bbDd bbdd BD Bd bD bd BD Bd
Blonde Dancing White Dancing
Blonde Non-Dancing White Non-Dancing

12. On Your Own
Now cross a white homozygous dancing hamster with a heterozygous blonde non-dancing hamster.
What are the genotypes of their offspring?
bbDD
Bbdd

13. Example of a Dihybrid Cross
Put the letter combinations from the alleles of the 1st parent above the boxes. bD bD bD bD

14. Example of a Dihybrid Cross
Now just follow the same steps as you would in a monohybrid cross.
This time there are just 4 letters instead of 2. bD bD bD bD Bd bd Bd bd

15. ____ ____ ____ ____ ____ ____ ____ ____
A heterozygous long haired alien with one eye meets a pretty alien who is homozygous both short hair and three eyes.
What are the genotypes of each alien?
___________ ___________
What are the allele combinations each alien could pass on to their kids?
____ ____ ____ ____ ____ ____ ____ ____

16. ____ ____ ____ ____ and ____ ____ ____ ____
A purebred green lip and purebred little nose alien is married to a hybrid green lip and hybrid big nosed alien.
What are the genotypes of each alien?
___________ x ___________
What are the allele combinations each alien could pass on to their kids?
____ ____ ____ ____ and ____ ____ ____ ____