Concept explainers
a.
To determine: The predicted genotypic ratio of the offspring produced between the cross of a parent with genotype Aa × aa.
Introduction: The alleles are inherited from the parents into the offsprings. The genotypic ratio represents the alleles that constitute the offspring while the
b.
To determine: The predicted genotypic ratio of the offspring produced between the cross of a parent with genotype Aa × Aa.
Introduction: The alleles are two variants of a gene. They are inherited from the parents to the offsprings. The genotypic ratio represents the alleles that constitute the offspring while the phenotypic ratio represents the external features of the offspring.
c.
To determine: The predicted genotypic ratio of the offspring produced between the cross of a parent with genotype AA × Aa
Introduction: The genotypic ratio is a means to represent the composition of the alleles that constitute the offspring while the phenotypic ratio represents the external characteristics expressed by the offspring.
Want to see the full answer?
Check out a sample textbook solutionChapter 3 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- Mendel performs a cross using a true-breeding pea plant with round, yellow seeds and a true- breeding pea plant with green, wrinkled seeds. What is the probability that offspring will have green, round seeds? Calculate the probability for the F1 and F2 generations.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 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 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_forwardMendel is growing flowers. Pure red flowers have a pair of R genes. Pure whiteflowers have a pair of w genes. Red is dominant to white.(a) Write the Punnett square with a pure red parent cross-fertilized with a pure white parent.(b) Write a second Punnett square of the offspring of the preceeding question cross-fertilizedwith a pure white flower.(c) What is the probability that a flower from the second fertilization is pure white? (Writethe probability as a fraction in reduced form.)arrow_forwardUsing Punnett Squares to Understand Inheritance Scenario 2: A truebreeding brown mouse is repeatedly mated with a true-breeding tan mouse, and all their offspring are tan. If two of these tan offspring from the F1 generation are mated, what fraction of the F2 mice will be tan? O They would all be brown O 1/2 O o 1/4 O 3/4 O Oarrow_forward
- Mendel examined two distinct flower phenotypes in his pea plants. Flower color and flower position. The violet color (W) is dominant over the white color (w), and the axial position (T) is dominant over terminal (t). Predict the F1 ratios of these phenotypes from a parent heterozygous for both traits and the other parent homozygous recessive for both traits. Show your work. Flower color Flower position violet/white axial/terminalarrow_forwardtype P = n! (p)* (q)"* х! (n - х)! Practice Problem: You cross a true-breeding pea plant with red flowers to a true-breeding pea plant with white flowers. All of your offspring have red flowers. Which gene is dominant? Why? What is the genotype of your offspring? You then cross the offspring to each other. What ratio do you expect? Why? You count 1000 plants and look at their flowers. Your results are as follows: 740 red 260 white Does this follow a simple Mendelian inheritance pattern? Why or why not? DADT 2 MEA SUDI ND D LUT IONSarrow_forwardDiscuss why Mendel's hybrid offspring begin to exhibit the original traits expressed by the P1 generation or the pure-breeding parents used in the original cross. What would happen if the hybrid offspring were allowed to breed without interference from Mendel for an extended period of time and the different ways plants can breed.arrow_forward
- Work out the Chi-Squared Goodness of Fit for Mendel's actual data on stem length: "Expt. 7: Length of stem. –– Out of 1,064 plants, in 787 cases the stem was long, and in 277 short. Hence a mutual ratio of 2.84:1. In this experiment the dwarfed plants were carefully lifted and transferred to a special bed. This precaution was necessary, as otherwise they would have perished through being overgrown by their tall relatives. Even in their quite young state they can be easily picked out by their compact growth and thick dark–green foliage." F2: O E O-E (O-E)^2 (O-E)^2/E # short 277 266 11 121 0.455 # tall 787 798 -11 121 0.152 sums: 1,064 1064 0.607 degrees of freedom = 2-1=1 Chi-squared value = .607 p-value: 0.25 < p < 0.50 Work out the Chi-Squared Goodness of Fit for Mendel's actual data on flower position: "Expt. 6: Position of flowers. –– Among 858 cases 651…arrow_forwardHelp mearrow_forwardOne Trait (Monohybrid) Crosses-Complete Dominance 1. In peas, inflated pod is dominant over wrinkled. If a homozygous inflated pod plant is crossed with a homozygous wrinkled pod plant, what will be the F₂ phenotypic ratio? 2. A tall pea plant crossed with a dwarf pea plant produces offspring of which about half are tall and half are dwarf. What are the genotypes of: a. the tall parent b. the dwarf parent 3. What does "test cross" or "backcross" mean?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStax