Concept explainers
More Crosses with Pea Plants: The Principle of Independent Assortment
Think about this one carefully. Albinism and hair color are governed by different genes. A recessively inherited form of albinism causes affected individuals to lack pigment in their skin, hair, and eyes. In hair color, red hair is inherited as a recessive trait and brown hair is inherited as a dominant trait relative to red hair. An albino woman whose parents both have red hair has two children with a man who is normally pigmented and has brown hair. The brown-haired partner has one parent who has red hair. The first child is normally pigmented and has brown hair. The second child is albino.
- a. What is the hair color (
phenotype ) of the albino parent? - b. What is the genotype of the albino parent for hair color?
- c. What is the genotype of the brown-haired parent with respect to hair color? Skin pigmentation?
- d. What is the genotype of the first child with respect to hair color and skin pigmentation?
- e. What are the possible genotypes of the second child for hair color? What is the phenotype of the second child for hair color? Can you explain this?
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Chapter 3 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- More Crosses with Pea Plants: The Principle of Independent Assortment Two traits are examined simultaneously in a cross of two pure-breeding pea-plant varieties. Pod shape can be either swollen or pinched. Pea color can be either green or yellow. A plant with the traits swollen and green is crossed with a plant with the traits pinched and yellow, and a resulting F1 plant is self-crossed. A total of 640 F2 progeny are phenotypically categorized as follows: 360 swollen yellow 120 swollen green 120 pinched yellow 40 pinched green a. What is the phenotypic ratio observed for pod shape? Pea color? b. What is the phenotypic ratio observed for both traits considered together? c. What is the dominance relationship for pod shape? Pea color? d. Deduce the genotypes of the P1 and F1 generations.arrow_forwardMore Crosses with Pea Plants: The Principle of Independent Assortment Consider the following cross in pea plants, in which smooth pea shape is dominant to wrinkled, and yellow pea color is dominant to green. A plant with smooth yellow peas is crossed to a plant with wrinkled green peas. The offspring produced peas that were all smooth and yellow. What are the genotypes of the parents? What are the genotypes of the offspring?arrow_forwardMore Crosses with Pea Plants: The Principle of Independent Assortment Determine the possible genotypes of the following parents by analyzing the phenotypes of their children. In this case, we will assume that brown eyes (B) is dominant to blue (b) and that right-handedness (R) is dominant to left-handedness (r). a. Parents: brown eyes, right-handed brown eyes, right-handed Offspring: 3/4 brown eyes, right-handed 1/4 blue eyes, right-handed b. Parents: brown eyes, right-handed blue eyes, right-handed Offspring: 6/16 blue eyes, right-handed 2/16 blue eyes, left-handed 6/16 brown eyes, right-handed 2/16 brown eyes, left-handed c. Parents: brown eyes, right-handed blue eyes, left-handed Offspring: 1/4 brown eyes, right-handed 1/4 brown eyes, left-handed 1/4 blue eyes, right-handed 1/4 blue eyes, left-handedarrow_forward
- More Crosses with Pea Plants: The Principle of Independent Assortment Consider the following cross: P1: AABBCCDDEE aabbccddee F1: AaBbCcDdEe (self-cross to get F2) What is the chance of getting an AaBBccDdee individual in the F2 generation?arrow_forwardCrossing Pea Plants: Mendels Study of Single Traits Stem length in pea plants is controlled by a single gene. Consider the cross of a true-breeding long-stemmed variety to a true-breeding short-stemmed variety in which long stems are completely dominant. a. If 120 F1 plants are examined, how many plants are expected to be long stemmed? Short stemmed? b. Assign genotypes to both P1 varieties and to all phenotypes listed in (a). c. A long-stemmed F1 plant is self-crossed. Of 300 F2 plants, how many should be long stemmed? Short stemmed? d. For the F2 plants mentioned in (c), what is the expected genotypic ratio?arrow_forwardMore Crosses with Pea Plants: The Principle of Independent Assortment Given the following matings, what are the predicted phenotypic ratios of the offspring? a. AABb Aabb b. AaBb aabb c. AaBb AaBbarrow_forward
- Choose one plsarrow_forwardThx!arrow_forwardShort is recessive to tall. Green pods are dominant to yellow as inflated pods are dominant to constricted pods. A pure-bred tall plant with green and inflated pods is crossed with a plant that is heterozygous for all of the traits. Calculate the probability of getting a plant seedling that is recessive for all of the traits. What is the probability of getting a tall plant with green and inflated pods?arrow_forward
- n pea plants, the appearance of flowers along the main stem is a dominant phenotype called axial and is controlled by the T allele. The recessive phenotype, produced by the E t allele, has flowers only at the end of the stem and is called terminal. Seedpod form iS determined by a second gene. The dominant phenotype inflated is controlled by allele C, and a recessive constricted form, produced by allele c. A pure breeding axial, constricted plant is crossed to one that is pure-breeding terminal, inflated. A. The F1 progeny of this cross are allowed to self-fertilize. What is the expected distribution of phenotypic classes among the F2 progeny? -> TTcc t난 CC x Et 1:2:1arrow_forwardLook at the diagram and use complete sentences to answer them please.arrow_forwardIn pea plants, round seeds are dominant to wrinkled seeds. Cross- A pea plant heterozygous for seed shape crossed with a pea plant that is homozygous recessive for seed shape. What percentage of their offspring will be homozygous? What percentage of their offspring will be wrinkled?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning