Concept explainers
A true-breeding plant with round and green seeds was crossed to a true-breeding plant with wrinkled and yellow seeds. The
To review:
The probability of obtaining the following plants in the F2 generation: two that have round and yellow seeds, one with round and green seeds, and two with wrinkled and green seeds.
Introduction:
True breeding plants are those plants which produce offsprings of the same type with same traits. Plant with genotype YY is an example of true breeding plant. Here Y represents the seed color that is yellow and it is easily visible that both the alleles are dominant forms and hence are true breeding.
Explanation of Solution
Genotypes to be used; RR: round, rr: wrinkled, Rr: round, YY: yellow, yy: green and Yy: yellow. Round is dominant over wrinkled seed whereas yellow seeds are dominant over green seeds. F1 plants are allowed to self-fertilize:
Gametes | R | r |
Y | RY | rY |
y | Ry | ry |
Results of selfing: RY, rY, Ry and ry. Further, crossing for F2 generation:
Gametes | RY | rY | Ry | ry |
RY | RRYY | RrYY | RRYy | RrYy |
rY | RrYY | rrYY | RrYy | rrYy |
Ry | RRYy | RrYy | RRyy | Rryy |
ry | RrYy | rrYy | Rryy | rryy |
Probability of round, yellow seeds:
Probability of round, green seeds:
Probability of wrinkled, green seeds:
Calculation with the help of multinomial equation:
Upon substituting the values in the equation:
Want to see more full solutions like this?
Chapter 2 Solutions
Genetics: Analysis and Principles
- In a variety of tomato plant ,the leaves maybe pure green,pure white,or variegated (mixture). a)when 2 variegated plants were crossed,87 offspring were produced,of these 20 were green,46 were variegated and 21 remain died soon after germination.Draw a genetic diagram to explain these results,why did 21 of them diedarrow_forwardAssume that the trihybrid cross AABBrr x aabbRR is made in a plant species. Assume that A and B are dominant alleles, but there is no dominance effect of alleles at the R locus. a) How many different gametes are possible in the F1generation? What are the genotypes of these gametes? b) What is the probability of the parental aabbRR genotype in the F2 progeny? c) What proportion of the F2 progeny would be expected to be homozygous for all three genes?arrow_forwardGiven the following information, determine the inheritance of flower color in this plant and determine the genotypes of the parental individuals, which are from pure- breeding lines. CROSS 1 CROSS 2 purple X colorless all purple 9/16 purple colorless X red all purple as in Cross 1 F1 F1 F2 F2 3/16 red 4/16 colorlessarrow_forward
- Consider this cross in pea plants: Tt Rr yy Aa × Tt rr Yy Aa, whereT = tall, t = dwarf, R = round, r = wrinkled, Y = yellow, y = green,A = axial, a = terminal. What is the expected phenotypic outcomeof this cross? Have one group of students solve this problem bymaking one big Punnett square, and have another group solve it bymaking four single-gene Punnett squares and using the multiplication method. Time each other to see who gets done first.arrow_forwardIn the Pea plant, tall plant height (T) is dominant over short (t). Pure-breeding tall and short plants are crossed. A) If the F1 is self-crossed and 400 F2 plants are raised, how many would be expected in each phenotypic class? B) How many of the F2 would be expected to be pure breeding when selfed?arrow_forwardNicotiana glutinosa (2 n = 24) and N. tabacum (2 n = 48) are two closely related plants that can be intercrossed, but the F1 hybrid plants that result are usually sterile. In 1925, Roy Clausen and Thomas Goodspeed crossed N. glutinosa and N. tabacum and obtained one fertile F1 plant . They were able to self-pollinate the flowers of this plant to produce an F2 generation. Surprisingly, the F2 plants were fully fertile and produced viable seeds. When Clausen and Goodspeed examined the chromosomes of the F2 plants, they observed 36 pairs of chromosomes in metaphase I and 36 individual chromosomes in metaphase II. Explain the origin of the F2 plants obtained by Clausen and Goodspeed and the numbers of chromosomes observed.arrow_forward
- Assume that, in a series of experiments, plants with round seeds were crossed with plants with wrinkled seeds and the following offspring were obtained: 215 round and 185 wrinkled. How do you explain these observations and what would be the expected number of offspring with round seed and with wrinkled seed? The plants with round seeds are heterozygous for the round seed phenotype and F1 offspring is expected to show 200 round and 200 wrinkled seed. The plants with round seeds are homozygous for the round seed phenotype and F1 offspring is expected to show 300 round and 100 wrinkled seed. The plants with round seeds are heterozygous for the round seed phenotype and F1 offspring is expected to show 100 round and 300 wrinkled seed. The plants with round seeds are homozygous for the round seed phenotype and F1 offspring is expected to show 200 round and 200 wrinkled seed. The plants with round seeds are heterozygous for the round seed phenotype and F1 offspring is…arrow_forwardA heterozygous pea plant that is tall with yellow seeds, TtGg, is allowed to self-fertilize. What is the probability that an offspring will be either tall with yellow seeds, tall with green seeds or dwarf with yellow seeds? Use the Sum Rule to calculate the probability asked in the problem.arrow_forwardA particular flower can be blue, red, or white. A pure-breeding red-flowered plant is crossed with a pure-breeding white-flowered one. The F 1 are then crossed to produce an F 2 generation. Which of the following phenotypic ratios in the F 2 indicate that flower color in these two strains is controlled by two genes? A)2:1 B)3:1 C)1:2:1 D)9:3:4arrow_forward
- In a trihybrid cross of a tall, purple-flowered pea plant with round seeds (TtPpRr) with a short, white- flowered pea plant with round seeds (ttppRr), what is the probability: A) that a short, white-flowered plant with wrinkled seeds will be produced? B) that a tall, purple-flowered plant with round seeds will be produced? C) that a tall, white-flowered plant with round seeds will be produced?arrow_forwardIn tomato plants, tall vine (D) is dominant over dwarf vine (d) and round fruit (O) is dominant over oval-shaped fruit (o). Two tall, round-fruit shape plants (plants 1 and 2) are crossed with dwarf, oval-shape fruit plants. The results are as follows: i) Why is there a difference in the proportionate number of plants in each phenotypic class of the offspring resulting from test crosses of plants 1 and 2? (ii) Calculate the recombination frequency between the genes D/d and O/o in tomatoes. (iii) Draw a chromosome map for these genes. (Use underscore (_) to draw the line for the map)arrow_forwardA pure breeding strain of squash that produced disk-shaped fruits was crossed with a pure- breeding strain having long fruits. The first filial generation had disk fruits, but the second filial generation showed a new phenotype, sphere, and was composed of the following proportions: disk 270, sphere 178, long 32. Propose an explanation for these results, and show the genotypes of P, First filial generation and second filial generation.arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education