Dihybrid Cross Practice Problems
1. A cross between two parent Reebops that are HETEROZYGOUS for TWO TRAITS is called a
________________________ cross.
MONOHYBRID DIHYBRID
2. Which of these Punnett squares would you use to show the possible offspring from this cross?
REEPOPS ARE SPECIAL, MADE UP BUGS. If a male with the genotype: TtHh is crossed with a
female with the genotype: TtHh
TtHh X TtHh
3. What are the possible GAMETES this Reebop can produce? (FOIL!!!!)
TtHh
CURLY TAILS = T
STRAIGHT TAILS = t
HOVERWINGS = H
NO WINGS = h
_____ _____ _____ _____
4. What phenotypic ratio would you expect to see in the offspring?
3:1
1:2:1
2:2
9:3:3:1
4:4:4:4
5. USE A PUNNETT SQUARE TO SHOW THE POSSIBLE OFFSPRING OF THE ABOVE CROSS:
What is the probability that an offspring will have CURLY TAIL and HOVERWINGS? ______/16
What is the probability that an offspring will have CURLY TAIL and NO WINGS? ______ /16
What is the probability that an offspring will have STRAIGHT TAIL and a HOVERWINGS? ____ /16
What is the probability that an offspring will have STRAIGHT TAIL and a NO WINGS? ____/16
6. You want to find out the probability of crossing two minions who are both heterozygous for having two eys (Ee) and
Heterozygous for being Tall (Tt). The genotypes of both parents are EeTt. Complete the Punnett Square Below and
answer the questions. (14pts)
7. How many of the offspring are:
_______Homozygous Dominant for both traits
_______Homozygous Dominant for Having Two
Eyes, Recessive for being short
_______Recessive for having one eye,
Heterozygous Dominant for being tall
_______Recessive for both traits
What is the ratio ____:____:_____:_____
Hint: DD: DR: RD: RR
8. Set up a punnett square using the following information:
Dominant allele for tall plants = D
Dominant allele for purple flowers = W
Recessive allele for dwarf plants = d
Recessive allele for white flowers = w
Cross a homozygous dominant parent (DDWW) with a homozygous recessive parent (ddww)
9.
How many offspring would be tall with
purple flowers?_______________
How many offspring would be tall with
white flowers?________________
How many offspring would be dwarf with
purple flowers?
How many offspring would be dwarf with
white flowers?
Using the info above, write the ratio:
____:____:_____:_____
(hint): DD:DR:RD:RR (Dominant,
Recessive)
10. Set up a punnett square using the following
information:
Dominate allele for normal coat color in wolves =N
Recessive allele for black coat color in wolves =n
Cross a heterozygous parent with a heterozygous parent.
Dominant allele for brown eyes = B
Recessive allele for blue eyes = b
11.
How many offspring would be normal coat
with brown eyes?_______________
How many offspring would be normal coat
with blue eyes?________________
How many offspring would be black coat
with brown eyes?______________
How many offspring would be black coat
with blue eyes?______________
Using the info above, write the ratio:
____:____:_____:_____
(hint): DD:DR:RD:RR (Dominant,
Recessive)