Download Genetics Homework Problems2

Genetics Homework
Mr. Barber’s Handy Hints for Punnett Square
Success.
1. Use capital letters for dominant alleles and lower
case letters for recessive alleles.
2. Make a key; A = Tall, a = short
3. Keep the parental genotypes intact.
4. Write the possible offspring genotypes and
phenotypes in each square.
Mendelian Inheritance Problems
5. Take your time! Sloppy work =
Monohybrid Homework Problems:
You must show all your work for full credit!
1. What genotype and phenotype ratios are possible
in the F1 and F2 generations from the cross of a
homozygous Round pea and a homozygous
wrinkled pea?
2. What genotype and phenotype ratios are possible
in the F1 and F2 generations from the cross of a
homozygous Purple flowered pea and a
homozygous white flowered pea?
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Dihybrid Cross Homework:
You must show all your work for full credit!
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1. What phenotype ratios are expected in the F1
and F2 generations from the cross of a pea that
is homozygous for Yellow peas in Inflated pods
and one with green peas in constricted pods?
2. What phenotype ratios are expected in the F1
and F2 generations from the cross of a truebreeding Tall pea with Axial flowers and a truebreeding short pea with terminal flowers?
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(Black is the dominant allele!)
3. What genotype and phenotype ratios are possible
in the F1 and F2 generations from the cross of a
homozygous Black hamster and a brown hamster?
4. What genotype and phenotype ratios are possible
in the F1 generation from the cross of a
heterozygous Black hamster and a brown hamster?
5. If the cross of Black and brown hamsters results in
a brown hamster (F1 generation). Prove the
genotype of the black hamster in the P generation?
3. What phenotype ratios are expected in the F1 and
F2 generations from the cross of a true-breeding
Black hamster with Short fur and a brown hamster
with long fur?
4. What phenotype ratios are expected in the F1 and
F2 generations from the cross of a true-breeding
Ebony colored fruit fly with short wings and a normal
colored fly with Long wings.
5. What phenotype ratios are expected in the F1
generation from the cross of a hybrid pea with
Purple Axial flowers and one with white terminal
flowers?
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Genetics Homework
Non-Mendelian Problems
Genetics Homework:
Multiple Alleles: Explain using a Punnett square how
two full color rabbits can have an albino kit.
Polygenic Traits: The color of wheat kernels is
determined by two gene pairs that produce a range
of colors from white to dark red. Red coloration is
dominant. Make a Punnett square and a line graph
showing the color distribution of the F1 resulting from
the cross of two double heterozygotes (AaBb X
AaBb)
Hint: Dark red, Red, Medium Red, Light Red, White
Genetics Homework:
Incomplete Dominance: Last year a lady grew white
snapdragons and red snapdragons in the same
flower bed. The plants cross-pollinated and the seed
grew this year. Construct two Punnett squares to
explain what color(s) of flowers to expect this year
and next year after this years flowers cross.
Codominance: A farmer wants to know which cow
the new white calf belongs to. Is it the roan cow’s or
the red cow’s if they were both bred to a roan bull?
Use two Punnett squares to prove your answer.
Genetics Homework:
Show how a father with type AB blood and a mother
with type O blood can have a child with type B blood.
Show all the possible parental blood genotypes
combinations of a child with type AB blood.
Show how two parents who are Rh+ can have a child
who is Rh-.
Use Punnett squares to solve these problems:
1. Mice have two genes for fur color. One
determines black or brown and the other
determines the presence of color or absence of
color.
What would the offspring of two mice who are
heterozygous for both traits look like?
2. What children are possible from a colorblind
male and a carrier female?
Is this a dominant or recessive disorder?
3. Show how a normal mother and father can
have a son with hemophilia.
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