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)
- In squirrels, bushy tail (B) is dominant to smooth tail (b), and gray coat (G) is dominant to brown coat (g). These two loci are linked. Pure-breeding gray, smooth-tailed squirrels were mated to pure-breeding brown, bushy-tailed squirrels. The F1 were testcrossed. Testcross progeny consisted of 278 gray, smooth-tailed, 21 gray, bushy-tailed, 306 brown, bushy-tailed, and 30 brown, smooth-tailed squirrels. Calculate the map distance between these two genes in centimorgans. Round your answer properly to 2 decimal digits. Type in only the numerical value for your map distance without indicating the units.arrow_forwardThe petals of the plant Collinsia parviflora are normally blue, giving the species its common name, blue-eyed Mary. Two pure-breeding lines were obtained from color variants found in nature; the first line had pink petals, and the second line had white petals. The following crosses were made between pure lines, with the results shown: Parents F1 F2 blue × white blue 101 blue, 33 white blue × pink blue 192 blue, 63 pink pink × white blue 272 blue, 121 white, 89 pink a. Explain these results genetically. Define the allele symbols that you use, and show the genetic constitution of the parents, the F1, and the F2 in each cross. b. A cross between a certain blue F2 plant and a certain white F2 plant gave progeny of which 3 8 were blue, 1 8 were pink, and 1 2 were white. What must the genotypes of these two F2 plants have been?arrow_forwardPurebred wrinkled, green-seeded pea plants were crossed with purebred round, yellow-seeded plants. The F1, all of which had round and yellow seeds, were then self-crossed resulting in the following F2: 172 plants with round and yellow seeds, 55 plants with round and green seeds, 58 plants with wrinkled and yellow seeds, and 15 plants with wrinkled and green seeds. Calculate the chi-square value and determine the p-value range. Which of the following are the correct chi-square values, p-value range, and whether you would accept or reject the hypothesis that these results are consistent with Mendelian predictions?arrow_forward
- In butterflies, blue wings (B) are dominant over yellow wings (b), and stripes (S) are dominant over no stripes (s). These genes for these two characteristics assort independently. A homozygous butterfly with yellow wings and no stripes is crossed with a homozygous butterfly that has blue wings and stripes. Afterward, individuals from this F1 generation were crossed obtaining a total of 272 butterflies as follows: 135 blue-winged butterflies with stripes, 55 blue with no stripes, 57 yellow with stripes, and 25 yellow without stripes. What is the X2 valuearrow_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. The F1 from (b) is then crossed to give an F2. What proportion would you expect in the F2 of each extreme phenotype?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. What is the contribution of each dominant allele to the phenotype in cm? The F1 from (b) is then crossed to give an F2. What proportion would you expect in the F2 of each extreme phenotype?arrow_forward
- A sex-influenced trait is dominant in bulls and causes horns. The same trait is recessive in cows and results in no horns. Fur color is not sex influenced, with black fur dominant to cream. A true breeding female with horns and black fur was crossed to a cream-colored male without horns. The F1 females were then crossed to hornless cream-colored males. The following results were obtained: Males: 30 hornless, black 68 hornless, cream-colored 74 horns, black 26 horns, cream-colored Females: 109 hornless, black 91 hornless, cream-colored 0 horns, black 0 horns, cream-colored Construct a chi square analysis to see if the genes are linked. If the genes are linked, compute the map distance between them.arrow_forwardGive only typing answer with explanation and conclusion A true-breeding pea plant with round and green seeds was crossed with a true-breeding plant with wrinkled and yellow seeds. Round and yellow seeds are the dominant traits. The F1 plants were allowed to self-fertilize. What are the following probabilities for the F2 generation? a. An F2 plant with wrinkled, yellow seeds. b. Two out of three F2 plants with round, yellow seeds and one with wrinkled, green seeds. c. Four F2 plants in the following order: one has round, yellow seeds; one has round, green seeds; and two have wrinkled, green seeds. d. An F2 plant will not have round, yellow seeds.arrow_forwardThe parental genotypes for a series of crosses are wild-type male fruit flies mated to females with white eyes (wh) and miniature (min) wings. The phenotypes of the F1 generation were wild-type females, and males with white eyes, and miniature wings. These flies were allowed to mate with each other and produced the following offspring: Red eyes, long wings White eyes, miniature wings Red eyes, miniature wings White eyes, long wings 770 716 401 318 Total 2205 A. Are these genes linked? Why or why not?arrow_forward
- In the pearl-millet plant, color is determined by three alleles at a single locus: Rp1 (red), Rp2 (purple), and rp (green). Red is dominant over purple and green, and purple is dominant over green (Rp1 > Rp2 > rp). Give the expected phenotypes and ratios of offspring produced by the following crosses. Q.Rp1/ rp × Rp2/ rparrow_forwardA fish with red eyes and yellow scales is crossed to a pure-breeding fish with brown eyes and orange scales, resulting in offspring having red eyes and yellow scales (50%) or brown eyes and yellow scales (50%). You cross the red eye/yellow scale offspring together, and the resulting offspring are as follows. How are these traits likely inherited Number of offspring 676-yellow/red 224-red/orange 224-brown/yellow 76-brown/orangearrow_forwardIn cat, a black cat when crossed with a white cat produces a tabby which appears to be a gray cat striped with black and white fur. What is the F1 phenotyphic ratio of a cross between a black and white cats? Numerical anwers only. When tabby cats are crossed with black cat. what is the phenotypic ratio of the offspring? Numerical anwers only. When tabby cats are crossed black cat. What is the phenotypes of the offspring? write in CAPITAL LETTERS WITH SEPARATE COMMAS When tabby cats are crossed with white cat. what is the phenotypic ratio of the offspring? Numerical anwers only. What is the specific mode of inheritance behind this phenomenon?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