Name: Block: Date: Black Chickens _ White Chicken Erminette Chickens

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1 Name: Block: Date: Honors Biology Incomplete/ Co-Dominance/ Multiple Alleles 1. Many genetic traits have a stronger dominant allele and a weaker recessive allele. This is known as complete dominance. Some traits, however, are NOT completely dominant and/or recessive. a. Summarize the difference between incomplete dominance and codominance. 2. In some chickens, the heterozygous genotype leads to a phenotype known as erminette, feathers which are speckled with both black AND white. The allele for Black is B and the allele for white is W. a. This is an example of which inheritance pattern (incomplete dominance or codominance)? b. For each phenotype below, identify the genotype. Black Chickens _ White Chicken Erminette Chickens 3. A black chicken is crossed with a white chicken. a. Give the expected genotypic and phenotypic ratios. 4. Two erminette chickens are crossed. a. Give the expected genotypic and phenotypic ratios. 5. In snapdragons, flower color is controlled by incomplete dominance. The allele for red is R and the allele for white is W. a. Knowing this trait is incompletely dominant, what would be the phenotype for the heterozygous condition (RW)? b. For each phenotype below, identify the genotype. Red Genotype: White Genotype: 2. Edward is extremely romantic and wants to give Bella an entire bouquet of pink snapdragons, her favorite flower. Unfortunately, Edward only has red snapdragons in his greenhouse. In order to produce the most number of pink snapdragons, what color flower should Edward cross with his red snapdragons? Show the punnett square to defend your answer. Is there a 2 nd choice where some pink snapdragons could be produced? Explain using punnett squares and your genotypic/phenotypic ratios.

2 6. The lubber grasshopper is a very large grasshopper, and is black with red and yellow stripes. Assume that red stripes are expressed from the homozygous genotype, yellow stripes from the homozygous genotype. What will be the genotypic and phenotypic ratios of the F 1 generation resulting from a cross of two grasshoppers, both with red and yellow stripes? What type of inheritance is this? a. Type of inheritance: 7. Moths will show 3 possible genotypes and phenotypes for wing color, red, orange, and yellow. The inheritance responsible for this is incomplete dominance. a. If an orange winged individual is crossed with a red winged individual, what will be the expected genotypic and phenotypic ratios that will be seen? b. Moths lay lots of eggs. Using the punnett square you created in a, suppose a parent produces 1,200 offspring. How many of the offspring will have yellow wings? c. Suppose from this cross, 950 offspring have orange wings. Is this possible? Explain why or why not. 8. Cattle have three colors. Red coat color and white coat in short horn cattle; with the heterozygous condition producing the roan condition. A farmer has a roan bull and a red herd of cows. How can he produce a pure breeding white herd, using only his present herd. Explain your answer. 9. Suppose you identify a new gene in mice. One of its alleles specifies white fur color. A second allele specifies brown fur color. Mice also are seen as white and brown patches. You want to determine whether the relationship between the alleles is simple dominance (and if so which color is dominant) incomplete or co-dominance. What sorts of genetic crosses would give you the answer? On what types of observations would you base your answers? Name the type of inheritance. 10. In horses, coat color comes in many varieties. If a brown horse is crossed with a white horse, the offspring are palominos (brown with white manes and tails). Name the type of inheritance. If a palomino horse is crossed with a white horse, what will the genotypic and phenotypic ratio of the F 1 be?

3 11. When roan cattle are mated, 25% of the offspring are red, 50% are roan, and 25% are white. Upon examination, it can be seen that the coat of a roan cow consists of both red and white hairs. What kind of inheritance is this? What were the original parental genotypes? Human blood types are determined by genes that follow the MULTIPLE ALLELES/CODOMINANCE pattern of inheritance. There are two dominant alleles (A and B) and one recessive allele (O). (Phenotype) Genotype Can donate blood to: Can receive blood from: O OO A,B,AB and O (universal donor) O AB AB AB A,B,AB and O (universal receiver) A AA or AO AB, A O,A B BB or BO AB,B O,B 7. Write the genotype for each person based on the description: a. Homozygous for the B allele b. Heterozygous for the A allele c. d. Type A and had a type O parent e. Type AB f. Blood can be donated to anybody g. Can only get blood from a type O donor 8. Pretend that Brad Pitt is homozygous for the type B allele, and Angelina Jolie is type O. What are all the possible blood types of their baby? 9. Draw a Punnett square showing all the possible blood types for the offspring produced by a type O mother and an a Type AB father 10. Mrs. Clink is type A and Mr. Clink is type O. They have three children named Matthew, Mark, and Luke. Mark is type O, Matthew is type A, and Luke is type AB. Based on this information: a. Mr. Clink must have the genotype b. Mrs. Clink must have the genotype because has blood type c. Luke cannot be the child of these parents because neither parent has the allele.

4 11. Two parents think their baby was switched at the hospital. Its 1968, so DNA fingerprinting technology does not exist yet. The mother has blood type O, the father has blood type AB, and the baby has blood type B. a. Mother s genotype: b. Father s genotype: c. Baby s genotype: or d. Punnett square showing all possible genotypes for children produced by this couple e. Was the baby switched? 12. Two other parents think their baby was switched at the hospital. The mother has blood type A, the father has blood type B, and the baby has blood type AB. a. Mother s genotype: or b. Father s genotype: or c. Baby s genotype: d. Punnett square that shows the baby s genotype as a possibility: e. Was the baby switched? 13. Based on the information in this table, which of the following could not be the father of the baby? Justify your answer with a Punnett square/s. Name Mother Baby Henry Phillip Eric John 14. Based on the information in this table, how would you explain the situation in regards to this baby s parents? Name Mother Baby Dennis Harold Danny Jacob 9. Explain why blood type data CANNOT prove who the father of a baby is, and can only prove who the father is not.

5 10. Human hair color is controlled by one gene with four alleles (some with incomplete dominance); H Br = brown H Bd = blonde h R = red h bk = black The possible genotypes and phenotypes H Bd H Bd or H Bd h bk = blonde H Bd H Br = mousy brown H Bd h R strawberry blonde H Br h R = auburn H Br H Br or H Br h bk = brown h R h R or h R h bk = red h bk h bk = black a. What do you think your parent s phenotypes and genotypes for hair color are? b. What are your phenotype and genotype for hair color? c. If someone with auburn hair has children with someone with red hair (but whose mother had black hair), what are the genotype and phenotype possibilities for their children? 11. Use your textbook to explain the difference between polygenic and pleiotropic traits. (Use your textbook)