Download CLASS SET Day 1 Monohybrid Cross Practice

CLASS SET
Day 1
Monohybrid Cross Practice
Oompa Loompa Genetics
1. OOmpas generally have gray faces, which is caused by a dominant gene. The recessive condition results in an
orange face. Develop a "key" to show the possible genotypes and phenotypes for the OOmpah's face colors.
2. Two heterozygous OOmpahs are crossed. What percentage of the offspring will have orange faces?
3. Otis Oompah has an orange face is married to Ona OOmpah who has a gray face. They have 60 Oompah
children, 30 of those children have orange faces. What is Ona and Otis OOmpah's genotype? _______________
Show the cross in a punnet square.
Fruit Fly genetics
4. In fruit flies, normal wings are dominant over vestigial wings. Cross two flies that are heterozygous for normal
wings. If there are 100 offspring produced, how many will have vestigial wings?
5. Suppose that after a cross between two flies, the following offspring were produced. What are the genotypes
and phenotypes of the parents?
?
?
?
Ff
Ff
?
Ff
Ff
Dihybrid Cross Practice
6. In the following plants round seed shape is dominant over wrinkled seed shape and yellow seed color is
dominant over green seed color. Determine the offspring expected when two pea plants, each
heterozygous for seed shape and seed color, are crossed.
a.
What are the chances of the offspring being homozygous for both round seed shape and yellow
seed color?
b. What are the chances of the offspring being homozygous for both wrinkled seed shape and
green seed color?
c. What are the chances of the offspring being heterozygous for both shape and seed color?
d. What is the phenotypic ratio?
7. In peas, round seed shape (R) is dominant to wrinkled seed shape (r), and yellow seed color (Y) is
dominant to green seed color (y). A pea plant which is homozygous round seed and has green seed color
is crossed with a pea plant that is heterozygous round seed shape and heterozygous yellow seed color.
a. What is the fraction of offspring that are homozygous for round seed?
b. What is the fraction of offspring that are homozygous for wrinkled seed?
c. What is the fraction of offspring that are homozygous for yellow seed color?
d. What is the fraction of offspring that are homozygous for green seed color?
e. What is the fraction of offspring that are heterozygous for both seed shape and color? Why?
f. What is the pheenotypic ratio?
8. A purebred wingless red-eyed fruit fly is crossed with a purebred winged sepia-eyed fruit fly to produce
F1 flies. fly to produce F1 flies.Two of the F1 flies are mated to produce an F2 generation of flies. What is
the phenotypic ratio of the F2 flies?
CLASS SET
Day 1
Dihybrid Cross Practice
*You must complete a dihybrid cross as evidence for your answer.
SpongeBob Genetics
1. SpongeBob is heterozygous for body shape and body color, he marries sponge Susie who has roundpants and is
blue. What percentage of their offspring will have squarepants and a blue body?
2. SpongeBob’s cousin SpongeBillyBob who has oval eyes and is heterozygous for squarepants marries a cute
squarepants gal, SpongeGerdy. They have 16 children and 8/16 have squarepants and round eyes what is
SpongeGerdy’s geneotype?
3. SpongeBob’s aunt, who is homozygous for squarepants is famous around town for her itty, bitty stubby nose!
She recently met a cute squarepants fellow who also has a long nose, though his mother has a stubby one. What
is the percent chance of SpongeBob’s aunt having a cute stubby nose squarepant bundle of joy.
Animal and Human Genetics
4. Some dogs bark when trailing and others are silent. The barking trait is due to a dominant gene. Erect ears are
dominant to drooping ears. What kind of pups would be expected from a heterozygous erect eared barker
mated to a droop eared silent trailer? What is the ratio of erect ear barker pups to droop ear silent pups?
5. Tongue rolling is dominant over non-rolling and right handedness is dominant over left handedness. If a left
handed man who is heterozygous for tongue rolling marries a right handed woman who is a non-roller what
fraction of their children would be left handed non-rollers, right handed non-rollers, and right handed rollers?
6. About 70 percent of Americans get a bitter taste from a chemical called phenyl thiocarbamide (PTC) and the
other taste nothing. The ability to taste it comes from a dominant gene while non-tasters have the recessive
gene. A woman with normal skin pigment who is a non-taster has a father who is an albino taster. She marries
an albino man who is a taster, but who has a mother who is a non-taster. What would the genotypic ratio be?
7. In humans black hair is dominant over red hair and having six fingers is dominant to having five fingers. Sally has
black hair and five fingers. Her father has red hair. Sally marries Bill who has red hair and six fingers. They have
children. Bill’s mother had five fingers. What fraction of their children will have red hair and five fingers? What
fraction of their children will have red hair and six fingers?
8. In the breeding season, male Anole lizards court females by bobbing their heads up and down while displaying a
colorful throat patch. Now, suppose that anoles prefer to mate with lizards who bob their heads fast (F) and
have red throat patches (R) and that these two alleles are dominant to their counterparts, slow bobbing and
yellow throats. A male lizard heterozygous for head bobbing and homozygous dominant for the red throat patch
mates with a female that is also heterozygous for head bobbing but is homozygous recessive for yellow throat
patches. How many of the F1 offspring have the preferred fast bobbing / red throat phenotype (assume 16
young)? What percentage of offspring will lack mates? What percentage of offspring will have trouble finding
mates?