Genotypes and Phenotypes Name:
Biology Date: Period:
Use the following information to answer the questions below.
R round seeds C colored seed coat G green pods
r wrinkled seeds c white seed coat g yellow pods
T tall plants I inflated pods B blue flowers
t short plants i constricted pods b black flowers
Y yellow seeds A axial flowers P purple stems
y green seeds a terminal flowers p pink stems
Give the Genotype.
1) Heterozygous inflated pods
2) Homozygous white seed coat
3) Homozygous round seeds
4) Heterozygous green pods
5) Heterozygous purple stems
6) Homozygous constricted pods
7) Homozygous green seeds
8) Heterozygous yellow seeds
9) Homozygous colored seed coat
10) Homozygous blue flowers
11) Homozygous black flowers and heterozygous tall plants
12) Heterozygous round seeds and homozygous pink stems
Give the Complete Phenotype.
11) Tt Cc
12) Bb Rr
1. In cabbage butterflies, white wings (W) are dominant to yellow wings (w). If a heterozygous white butterfly is crossed with a yellow butterfly, what are the possible genotypes and phenotypes of the offspring and the
percent chance for each?
2. In dogs, there is a hereditary type of deafness caused by a recessive gene (d). Two dogs are mated, both carry the gene for deafness but have normal hearing. What are the possible genotypes and phenotypes of
their offspring and the percent chance for each?
3. In guinea pigs, short hair (H) is dominant over long hair (h). If a pure short haired guinea pig is crossed with a long haired guinea pig, what are the possible genotypes and phenotypes of their offspring and the percent
chance of each?
4. Can you curl your tongue up on the sides? Tongue-curling (T) in humans is a dominant genetic trait. Suppose a man who is hybrid for tongue-curling marries a woman who is also hybrid for this trait. What are
the possible genotypes and phenotypes of their children and the percent chance for each?
5. In guinea pigs, rough coats with lots of swirly cowlicks (R) are dominant over smooth coats (r). If a pure rough coat guinea pig is crossed with a heterozygous rough coat guinea pig, what are the possible genotypes
and phenotypes of the offspring? What are the chances of each?
Pictured at the right is an alien who displays all of the dominant characteristics of its species.
Below is a chart listing various traits found in this alien race. Use the information in the chart to
solve the genetics problems that follow. Use Punnett Squares to show your work.
Trait Dominant Phenotype Recessive Phenotype
Body color (Y) Yellow (y) Orange
Number of Antennae (A) 2 (a) 1
Eye color (P) Purple (p) White
Eyesight (E) Glasses needed (e) Glasses not worn
Number of Body Rings (R) 3 (r) 5
Note: pure refers to a homozygous genotype and hybrid refers to a heterozygous genotype.
1. A male heterozygous for body color mates with a pure yellow female. What is the chance this couple will produce an orange baby?
2. Two purple-eyed aliens mate. Both aliens are hybrid for the eye color trait. What is the chance this couple will produce a baby with a homozygous recessive genotype?
3. A 5-ringed female mates with a 5-ringed male. The 5-ringed female had parents with 3 body rings. What is the chance that this couple will have a baby that looks like its maternal grandparents?
4. A pure male alien displaying the dominant body color mates with a female that is homozygous recessive for this characteristic. What is the chance that this couple will have a baby with a hybrid genotype?
5. A male alien, with 1 antenna, mates with a female alien who has 2 antennae. The female is heterozygous for the antenna trait. What is the chance that this couple will produce a baby with the recessive phenotype?
6. An alien couple, both of which wear glasses, is having a baby. The male's genotype is heterozygous. The female is phenotypically dominant but does carry the recessive allele. What is the chance that this couple's
baby will have to wear glasses?
7. A three-ringed female mates with a homozygous male. The female has been genetically tested and is carrying both the dominant and the recessive allele for this trait. The male displays the recessive
phenotype. What is the chance that this couple will have a genetically pure baby?
Extra Practice Problems: 1. Woodrats are medium sized rodents with lots of interesting behaviors. You may know of them as packrats. Let's
assume that the trait of bringing home shiny objects (H) is dominant to the trait of carrying home only dull objects (h).
Suppose two heterozygous individuals are crossed. How many of each genotype would be expected if only 4 offspring
were produced? How many of each phenotype?
2. Saguaro cacti are very tall cylindrical plants that usually have two L-shaped arms, one on each side. Suppose you lived in southern Arizona where the Saguaro cactus is common and you happen to have one growing in your yard.
Your Saguaro has two arms but one is longer than the other. Now, assume that arm length in these cacti is controlled
by a single gene with arms of the same length (A) being dominant to arms of different lengths. What is the genotype
of your cactus? Could one of the parents of your cactus have had a phenotype with arms the same length? If so, what
would have been the genotype of that parent?
3. The common grackle is a species of robin-sized blackbirds that are fairly common (hence the name) over most of the United States. Suppose that long tails (T) were dominant to short tails in these birds. A female short-tailed grackle
mates with a male long-tailed grackle who had one parent with a long tail and one parent with a short tail. What is the
male's genotype? How many of each genotype will be found in the F1 generation? How many of each phenotype will
be found in the F1 generation?
4. In cattle, the polled (hornless) condition is caused by a dominant allele (H), while the recessive allele causes horns to grow. A polled cow and a polled bull produce a calf which grows horns as it matures. Show the genotypes of all three.
What is the probability that the pair's next calf will also grow horns?
5. In dogs, wire hair (W) is dominant to smooth (w). In a cross of a homozygous wire-haired dog with a smooth-haired dog, what will be the phenotype of the offspring (F1 generation)? What would the genotype be? What would be the
ratio of wire-haired to smooth-haired dogs in the F2 generation? Hint: think of Mendels experiments to determine
the cross for the F2 generation.
1. Tall plants (T) are dominant over short plants. Round seeds (R) are dominant over wrinkled seeds. What would be the results of a cross between two pea plants that were heterozygous for both tall and round seeds?
Show a Punnett square and state the phenotypic ratios.
2. Parent 1 is heterozygous for skin color (green (G) is dominant over purple) and homozygous for eating people (eating (E) is dominant over non-eating). Parent 2 is purple and does not eat people. Give the
genotype and phenotypes of the possible offspring.
3. In lizards, yellow (Y) belly is dominant over white and sap sucking is recessive to non-sap sucking (S). If one lizard is heterozygous non-sap sucking with a white belly and the other lizard is heterozygous non-
sap sucking with a yellow belly, what are the genotype possibilities and phenotypes of the offspring?
4. Gray (G) is dominant over pink in elephants. No polka dots (D) is dominant over polka dots. If the father is homozygous for both traits (gray and no polka dots) and the mother is homozygous recessive for both traits,
will any of the offspring look like the mother? Give the genotypes of the parents and the genotypes
and phenotypes offspring.
5. Cross a heterozygous gray with no dots with the mother in the previous question. Give the genotypes and phenotypes possible in the children.
6. In rabbits, black is due to a dominant factor (B), brown to its recessive allele (b). Short hair (S) is dominant over long hair (s). In a cross between a homozygous black, short haired female and a homozygous brown
long haired male, what would be the genotypic constitution and appearance of the F1 generation? Of
the F2 generation?
7. In horses, black is dependent upon a dominant facto