Genetic Problems Buffet
Instructions: Choose problems from each section to total 100 points. Appetizers are worth 5 points,
entrees are worth 10, and desserts are 15 points. On your own sheet of paper, write you menu and then,
for each part, have the answers (with the #) for the ones you choose, including your work. Therefore, you
can choose one of the combinations given below or make your own to get at least 100 points.
Suggested combinations:
Home Cooking
Appetizers (9)
45 pts.
Entrée (4)
40 pts.
Dessert (1)
15 pts.
Appetizers
House Special
Appetizers (5)
25 pts.
Entrée (3)
30 pts.
Dessert (3)
45 pts.
Five Star Restaurant
Appetizers (3)
15 pts.
Entrée (4)
40 pts.
Dessert (3)
45 pts.
5 points each
A1) In a certain plant, green seeds (G) are dominant to yellow seeds (g). If a farmer crossed two plants that are
both heterozygous for green, what would be the possible genotypes of the offspring?
A2) In certain animals, black fur (B) is dominant to white fur (b). Cross a homozygous black animal with a
white animal. What are the possible genotypes and phenotypes of the offspring?
A3) In certain animals, black fur (B) is dominant to white fur (b). Cross two heterozygous black animals.
What is the genotypic phenotypic rations of the offspring?
A4) In certain animals, black fur (B) is dominant to white fur (b). Cross a heterozygous black animal with a
white animal. What are the possible genotypes and phenotypes of the offspring?
A5) In humans, right handedness is dominant over left handedness. If a homozygous right handed person is
crossed with a homozygous left handed person, what are the possible genotypes and phenotypes of the
children?
A6) In humans, right handedness is dominant over left handedness. If a heterozygous right handed person is
crossed with another heterozygous right handed person, what are the possible genotypes and phenotypes of the
children?
A7) Round seeds(R) are dominant to wrinkled seeds (r) .Cross a heterozygous round seed plant with a wrinkled
seed plant. What percentage of the offspring will be round?
A8) A tall plant (TT) is crossed with a short plant (tt). What is the probability that the offspring will be tall?
A9) In pea plants, purple flowers are dominant to white flowers. If two white flowered plants are crossed,
what percentage of their offspring will be purple?
A10) Show the cross for a pure breeding purple (P) flowering plant with a white (p) flowering plant. What are
the possible genotypes and phenotypes of the offspring?
Entrees
10 points each
E1) Suppose that in outer space there exist creature in which purple eyes are dominant to yellow eyes. Two
purple-eyed creatures mate and produce six offspring. Four of them have purple eyes and tow of them have
yellow eyes. What are the genotypes and phenotypes of the parents?
E2) If two parents are both heterozygous for brown eyes, what is the probability that they will produce a child
with blue eyes?
E3)Two plants were crossed and the results were 298 purple flowered offspring and 102 white flowered
offspring. What were the genotypes of the parents?
E4) One parent is heterozygous for brown eyes and the other parent has blue eyes. What is the probability that
they will have a child with blue eyes?
E5) In guinea pigs, black fur is dominant to white fur. Is it possible for a white guinea pig whose parents are
both black, to have grandfather that is homozygous black? Why or why not?
E6) If a family with eight children had four with brown eyes and four with blue eyes, what is the probability
that the mother has the genotype bb?
E7) Could a child that is right handed have parents that are both left handed? Explain.
E8) Could a child that is left handed have parents that are both right handed? Explain.
E9) In guinea pigs, the allele for short hair is dominant. Two short haired guinea pigs are mated several times.
Out of 100 offspring, 25 of them have long hair. What are the probable genotypes of the parents?
E10) In humans, right handedness is dominant over left handedness. If a homozygous right handed person is
crossed with a homozygous left handed person, what are the possible genotypes and phenotypes of the F2
generation?
Desserts
15 points each
D1) A man with type AB blood is married to a woman also with type AB blood. What percentage of their
children will have: A blood? _______ B blood? ______ O blood _____ AB blood ________
D2) A man with type AB blood is married to a woman with type O blood. They have two natural children and
one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child
was adopted?
D3) In fruit flies, red eyes (R) is dominant to magenta (r), and long wing (L) is dominant to short wing (l). If a
heterozygous red eyed, short winged male is bred to a magenta eyed, heterozygous long winged female, what
percentage of their offspring would have magenta eyes and short wings?
D4) In horses, black is dominant to chestnut. The trotting gait of horses is due to the dominant gene (T), while
the pacing gate is due to the recessive gene (t). If a homozygous black pacer is mated to a homozygous chestnut
trotter, what will the genotypes and phenotypes of the offspring be?
D5) In cattle, black coat (R) is dominant to red coat (r). Hornless (H) is dominant to horned (h). A certain
bull was mated to four cows. Cow 1, black and hornless gave birth to a hornless red calf. Cow 2, hornless and
red, gave birth to a horned black calf. Cow 3, horned and black, gave birth to a horned red calf. Cow 4, horned
red, gave birth to a hornless black calf. What is the genotype of the bull? What are the possible genotypes of
the cows and their calves?
D6) Calico is a coat color found in cats, which is caused by a SEX-LINKED, CODOMINANT
allele. B = black, R = orange, and BR = calico. The following genotypes are possible: Female
cats can be black XBXB, orange XRXR, or calico XBXR. Male cats can be black XBY or orange XRY.
Cross a black male crossed with a calico female. What are the possible genotypes and phenotypes of the
offspring?
D7) See D4 for information about cats. Cross an orange male cat with a black female. What is the phenotypic
ratio of the offspring?
D8) In humans, hemophilia is a sex linked trait. Females can be normal, carriers, or have the disease. Males
will either have the disease or not (but they won’t ever be carriers). A woman who is a carrier marries a normal
man. What is the probability that their children will have hemophilia? What sex will a child in the family with
hemophilia be?
D9) In humans, hemophilia is a sex linked trait. A woman who has hemophilia marries a normal man. How
many of their children will have hemophilia, and what is their sex?
D10) If a mother is heterozygous for type A blood and the father has type AB, what would be the genotypes for
both parents and all six of their children?