Concept explainers
In Dexter and Kerry cattle, animals may be polled (hornless) or horned. The Dexter animals have short legs, whereas the Kerry animals have long legs. When many offspring were obtained from matings between polled Kerrys and horned Dexters, half were found to be polled Dexters and half polled Kerrys. When these two types of F1 cattle were mated to one another, the following F2 data were obtained:
3/8 polled Dexters
3/8 polled Kerrys
1/8 horned Dexters
1/8 horned Kerrys
A geneticist was puzzled by these data and interviewed farmers who had bred these cattle for decades. She learned that Kerrys were true breeding. Dexters, on the other hand, were not true breeding and never produced as many offspring as Kerrys. Provide a genetic explanation for these observations.
Want to see the full answer?
Check out a sample textbook solutionChapter 4 Solutions
Concepts of Genetics (12th Edition)
- If one human parent is heterozygous for blood type A (IAi), and the second parent is heterozygous for blood type B (IBi), what are the expected phenotypic ratios in their children? a. 1/4 with blood type AB, 1/4 with blood type A, 1/4 with blood type B, and 1/4 with blood type O b. 1/4 with blood type A (IAi), 1/2 with blood type AB (IAIB), and 1/4 with blood type B (IBi) c. 1/2 with blood type AB (IAIB), and 1/2 with blood type O (ii) d. 1/2 with blood type A (IAi), and 1/2 with blood type B (IBi) e. 1/2 with blood type A (IAi), and 1/2 with blood type O (ii)arrow_forwardYou have a pure breeding plant with red flowers, yellow seeds and red-veined leaves. You cross this with another pure breeding plant that has white flowers, pink seeds and yellow leaf veins. All of the offspring (F1) have white flowers, yellow seeds and orange leaf veins. Assuming all three loci are independently assorting, use this information to answer the following question: If two F1 offspring are crossed with each other and 1000 F2 are obtained, approximately how many offspring should have orange leaf veins? a. 1000 b. 750 c. 500 d. 250 e. Cannot be determined with this informationarrow_forwardYou start a cross with a true-breeding red-eyed troll and a true-breeding white-eyed troll, and then cross the F1 offspring to make the F2 generation. In the F2 generation, you collect 3 red-eyed trolls, 8 white-eyed trolls, and 5 pink-eyed trolls. Use a chi-square test to evaluate whether the data matches your expectation if the trait is controlled by a single gene with incomplete dominance. In the spaces below, enter the expected number of offspring in each phenotypic group that you would use to calculate your chi square. Report your expected values to the nearest 0.01. Expected Number of Pink-eyed trolls Expected Number of Red-eyed trolls Expected Number of White-eyed trolls Calculate your chi-square test and answer the following questions: How many degrees of freedom do you have in this test Do you reject the null hypothesis? Yes or no?arrow_forward
- Most of the individuals of a certain wildflower population have yellow flowers, although a few are white-flowered. Crosses have demonstrated that allele for yellow flower (Y) is dominant over the allele for white (y). If two white flowered plants are crossed, what fraction of their offspring do you expect to be YELLOW? Show your solution with punnet squarearrow_forwardA homozygous plant with 20-cm-diameter flowers is crossed with a homozygous plant of the same species that has 40-cm-diameter flowers. The F1 plants all have flowers 30 cm in diameter. In the F2 generation of 512 plants, 2 plants have flowers 20 cm in diameter, 2 plants have flowers 40 cm in diameter, and the remaining 508 plants have flowers of a range of sizes in between. (a) Assuming all alleles involved act additively, how many genes control flower size in this plant? (b) What frequency distribution of flower diameter would you expect to see in the progeny of a backcross between an F1 plant and the large-flowered parent?arrow_forwardMost of the individuals of a certain wildflower population have yellow flowers, although a few are white-flowered. Crosses have demonstrated that allele for yellow flower (Y) is dominant over the allele for white (y). If two heterozygous yellow-flowered plants are crossed, what fraction of the offspring do you expect to be white? Show your solution.arrow_forward
- The allele A is brown fur and the allele a is white fur. In a mating between a heterozygous male and a heterozygous female, what is probability that they will have an offspring with brown fur and what is the probability they will have an offspring with white fur?arrow_forwardWhat would the genotypes and genotypic ratio be for the F2 generation produced in a phenotype and phenotypic ration of F1 individuals that were produced from a male blue tailed gecko crossed with a female green tailed gecko, being that all 28 of the offspring had green tails, were mated brother and sister?arrow_forwardTwo true-breeding varieties of maize, one 11 cm high and the other 47 cm high were crossed and the resultant F1 hybrids were then crossed to generate the F2 . In the F2 there were a total of 13,923 plants with a continuous variation in heights between the two extremes and with only 3 plants as large as 47 cm high and 5 plants of 11 cm high.SO In a cross between a 29cm plant and a 20cm plant what would be the genotypes giving the smallest number of different phenotypes? specify the phenotypes observed.arrow_forward
- In corn plants, a dominant allele Z inhibits kernel color, while the recessive allele z permits color when homozygous. At a different locus, the dominant allele X causes purple kernel color, while the homozygous recessive genotype causes red kernel color. If corn plants heterozygous for both the Z and X genes are crossed, what are the chances that the offspring will have purple kernels? Enter your answer as a decimal fraction in the box (e.g. 0.25).arrow_forwardThe long hair of Persian cats is recessive to the short hair of Siamese cats, but the black coat color of Persians is dominant to the brown-and-tan coat color of Siamese. Make up appropriate symbols for the alleles of these two unlinked loci. If a pure black, long-haired Persian is mated to a pure brown-and-tan, short-haired Siamese, what will be the appearance of the F1 offspring? If two of these F1 cats are mated, what is the chance that a long-haired, brown-andtan cat will be produced in the F2 generation? (Use the shortcut probability method to obtain your answer; then check it with a Punnett square.)arrow_forwardIn peas, purple flowers are dominant to white. If a purple-flowered, heterozygous plant were crossed with a white-flowered plant, what is the expected ratio of genotypes and phenotypes among the F1F1offspring? If two of the purple-flowered F1F1 offspring were randomly selected and crossed, what is the expected ratio of genotypes and phenotypes among the F2F2 offspring?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