Download In dogs, there is an hereditary deafness caused by a recessive gene

Name ____________________________________ Date ________________ Group _____ Period_______
Mendelian & Non-Mendelian Punnett Squares Part 1: Monohybrid and dihybrid dominant
and recessive inheritance, incomplete dominance and codominance will be used in the following
questions.
1. In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man marries a
blue-eyed woman and they have three children, two of whom are brown-eyed and one of
whom is blue-eyed.
a. What is the woman’s genotype? ____________________________________
b. What are the man’s possible genotypes? ______________________________
c. Draw the two possible Punnett squares that could illustrates this marriage.
d. What are the genotypes of the children?
e. Which genotype does the man have to be?
2. The ability to curl your tongue up on the sides (T, tongue rolling) is
dominant to not being able to roll your tongue. A woman who can roll her
tongue marries a man who cannot. Their first child has his father's phenotype.
What are the genotypes of the mother, father, and child?
a. Mother ________________________________
b. Father _________________________________
c. Child __________________________________
3. In dogs, there is an hereditary deafness caused by a recessive gene, “d.” A kennel owner has a male dog that she wants
to use for breeding purposes if possible. The dog can hear, so the owner knows his genotype is either DD or Dd. If the
dog’s genotype is Dd, the owner does not wish to use him for breeding so that the deafness gene will not be passed on.
This can be tested by breeding the dog to a deaf female (dd).
a. Draw the Punnett squares to illustrate these two possible crosses.
b. In each
case, what
offspring would be expected to be hearing? deaf?
percentage/how many of the
c. How could you tell the genotype of this male dog?
d. Using Punnett square(s), show how two hearing dogs could produce deaf offspring.
4. In northeast Kansas there is a creature know as a puma. It comes in three colors, blue, red, and
purple. This trait is controlled by a single gene with incomplete dominance. A homozygous (BB)
individual is blue, a homozygous (RR) individual is red, and a heterozygous (BR) individual is
purple.
a. Using a Punnett square, cross a blue puma with a red puma.
b. What would be the possible genotypes and phenotypes of the offspring resulting from the previous cross?
c. Using a Punnett square, cross two purple pumas.
d. What would be the possible genotypes and phenotypes of the offspring resulting from the previous cross?
Part 2: Multiple Alleles
Key for following problems.
C = full color (brown); dominant to all other alleles.
cch = grey; dominate to ch and c alleles
ch = yellow; dominate to c allele
c = white; recessive to all other alleles
5. What are the possible genotypes for a
brown animal? __________________________________________
grey animal? ____________________________________________
yellow animal? __________________________________________
white animal? ___________________________________________
6. A geneticist studying coat color in animals crosses a male rabbit having the genotype CC with a female having a
genotype of Ccch. The geneticist then crosses a ccch male with a Ccc female. In which of the two crosses are the offspring
more likely to show greater genetic variation? Use Punnett Squares to explain your answer.
7. When a blue flower is crossed with a red flower, it makes a blue flower with red polka dots. What type of dominance
is this?
8. Using the info from #7 show the cross & expected genotypes and phenotypes when a blue flower is crossed with a
polka dotted flower.