Unformatted text preview: SHOW YOUR WORK! 1. Explain each of the following, and give an example: dominant disease, recessive disease, X-
Iinked disease, a pleiotrophic disorder, epistasis, multifactorial, polygenic traits, codominance,
and incomplete dominance SHOW YOUR WORK! 2. A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When the
albino was crossed with a different black guinea pig, 7 blacks and 5 albinos were obtained. a. What is the best explanation for this genetic situation? b. Write genotypes for the parents, gametes, and offspring 3. l have a pea plant with purple flowers and round peas. How can you determine : the genotype
of this plant for each character and whether they follow the law of independent assortment? SHOW YOUR WORK! 4. Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a
white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or
long, with long being dominant. If true-breeding red long radishes are crossed with true-
breeding white oval radishes, what will the offspring look like? 5. What does it mean to be a carrier for a trait? 6. A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of
normal height. The man's father was 6 feet tall, and both the woman's parents were of average
height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-
linked recessive. How many of their daughters might be expected to be color-blind dwarfs? Name Period AP Biology Date GENETICS PRACTICE 1: BASIC MENDELIAN GENETICS Solve these genetics problems. Be sure to complete the Punnett square to show how you
derived your solution. 1. In humans the allele for albinism is recessive to the allele for normal skin pigmentation. If
two heterozygotes have children, what is the chance that a child will have normal skin pigment? What is the chance that a child will be albino? normal pigment: albino: W a. If the child is normal, what is the chance that it is
a carrier (heterozygous) for the albino allele? (CAREFUL!) 2. In purple people eaters, one-horn is dominant and no horns is recessive. Show the cross of
a purple people eater that is heterozygous for horns with a purple people eater that does not
have horns. Summarize the genotypes & phenotypes of the possible offspring? 3. In humans, the brown-eye (B) allele is dominant to the blue-eye allele (b). If two
heterozygotes mate, what will be the likely genotype and phenotype ratios of the offspring. E 1 of 2
Developed by Kim B. Foglia - - ©2008 Name AP Biology 4. In seals, the gene for the length of the whiskers has two alleles. The dominant allele (W)
codes long whiskers & the recessive allele (w) codes for short whiskers. What percentage of
offspring would be expected to have short whiskers from the cross of two long-whiskered
seals, one that is homozygous dominant and one that is heterozygous? 5. In pea plants, the green color allele (G) is dominant over yellow color allele (9) for seed color
and tall (T) is the dominant allele in plant height. Parents heterozygous for both traits are
cross-pollinated. Determine the frequency for the four different phenotypes of the offspring. Tall plant, green seeds: Tall plant, yellow seeds: Short plant, green seeds: ‘ Short plant, yellow seeds: 6. Now let’s try a shortcut way of solving that same dihybrid cross. Because of Mendel's (2“)
Law of Independent Assortment, you can work with the color gene and the height gene
separately... so set up two separate monohybrid crosses from those same parents: E Now use the laws of probability to calculate your frequencies of each trait alone and combined: Tall plant, green seeds Tall plant, yellow seeds 20f2 Name Period AP Biology Date GENETICS PRACTICE 2: BEYOND THE BASICS Solve these genetics problems. Be sure to complete the Punnett square to show how you
derived your solution. INCOMPLETE DOMINANCE 1. In radishes, the gene that controls color exhibits incomplete dominance. Pure-breeding red
radishes crossed with pure-breeding white radishes make purple radishes. What are the
genotypic and phenotypic ratios when you cross a purple radish with a white radish? 2. Certain breeds of cattle show incomplete dominance in coat color. When pure breeding red
cows are bred with pure breeding white cows, the offspring are roan (a pinkish coat color).
Summarize the genotypes & phenotypes of the possible offspring when a roan cow is mated with a roan bull CO-DOMINANCE 3. A man with type AB blood marries a woman with type B blood. Her mother has type 0
blood. List the expected phenotype & genotype frequencies of their children. 1 of 2
Developed by Kim B. Foglia - - ©2008 Name AP Biology 4. The father of a child has type AB blood. The mother has type A.
Which blood types can their children NOT have? 5. A woman with type A blood and a man with type B blood
could potentially have offspring with what blood types? 6. The mother has type A blood. Her husband has type B blood.
Their child has type 0 blood. The father claims the child can’t
be his. Is he right? 7. The mother has type B blood. Her husband has type AB blood.
Their child has type 0 blood. The father claims the child can‘t
be his. Is he right? 8. The mother has type AB blood. The father has type B blood.
His mother has type 0 blood. What are all the possibilities of
blood type for their children? LETHAL DOMINANT 9. Achondroplasia (dwarfism) is caused by a dominant gene. A woman and a man both with
dwarfism marry. lf homozygous achondroplasia results in death of embryos, list the
genotypes and phenotypes of all potential live-birth offspring. What is the expected ratio of dwarfism to
normal offspring? SEX-LINKED 10. The genes for hemophilia are located on the X chromosome. It is a recessive disorder. List
the possible genotypes and phenotypes of the children from a man normal for blood clotting
and a woman who is a carrier. (HINT: You have to keep track of what sex the children are!) EXTRA CREDIT: Remember those roan cows from question 2? They also have a second gene
for horn vs. hornless cattle. The allele for horns dominates the allele for hornless. If a bull and cow are heterozygous for both genes, what are the probabilities for each possible phenotype? 20f2 ...
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- Summer '13