Concept explainers
In chickens, the presence of feathers on the legs is due to a dominant allele (F), and the absence of leg feath-ers is due to a recessive allele (f). The comb on the top of the head can be either pea-shaped, a
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
GENETIC ANALYSIS: AN INTEG. APP. W/MAS
- In the yawncat (a rare hypothetical animal), the dominant allele R causes solid tail color, and the recessive allele r results in white spots on a colored background. The black coat color allele B is dominant to the brown allele b, but the B and b alleles can only be expressed if the animal has an mm genotype at a third gene locus. Animals that are M_ are yellow regardless of which allele from the B locus is present. A mating between a solid yellow-tailed male yawncat and a solid brown-tailed female yawncat produces 16 offspring with the following tail phenotypes: six solid yellow, two spotted yellow, three solid black, one spotted black, three solid brown, and one spotted brown. What is the probability of the next offspring from these same two parents having a spotted brown tail? O A. 1/16 B. 9/16 С. 3/16 D. 1/2 O E. 1/4arrow_forwardIn chickens, comb shape is determined by genes at two loci (Gene 1 has alleles R, r and Gene 2 has alleles P, p). A walnut comb is produced when at least one dominant gene R is present at one locus and at least one dominant gene P is present at a second locus (genotype R_P). The genotype R_pp gives a rose comb phenotype; rrP_gives a pea comb phenotype; and rrpp gives a single comb phenotype. Based on this information give specific genotypes for comb shape of the parents in the crosses listed below: A) Walnut crossed with single produces 1 walnut, 1 rose, 1 pea and 1 single offspring. B) Rose crossed with pea produces 20 walnut offspring. C) Pea crossed with single produces 1 single offspring.arrow_forwardIn Shorthorn cattle, coat color is controlled by a single gene thatcan exist as a red allele (R) or a white allele (r). The heterozygotes (Rr) have a color called roan that looks less red than theRR homozygotes. However, when examined carefully, the roanphenotype in cattle is actually due to a mixture of completelyred hairs and completely white hairs. Should this be calledincomplete dominance, codominance, or something else?Explain your reasoningarrow_forward
- In mice, the presence of a dominant A allele results in the agouti pattern of fur color, whereas the aa homozygous recessive results in a solid color pattern. The presence of another dominant B allele results in black fur color, whereas the homozygous recessive bb results in brown fur color. The presence of a third dominant C allele is required for any color to be observed (brown or black), whereas the homozygous recessive cc results in lack of any color whatsoever (albino). What is the phenotype of a mouse with the following genotype? Aa bb cc albino Agouti color pattern and brown Solid color pattern and brown Agouti color pattern and black Solid color pattern and blackarrow_forwardIn Labrador retriever dogs, two alleles (B and b) determine whether coat colour will be black (B)or brown (b). Black coat colour is dominant. A second pair of alleles, E and e, are on a separatechromosome from B and b. The homozygous recessive condition, ee, prevents the expressionof either allele B or b, and produces a dog with a yellow-coloured coat. Some examples ofgenotypes and phenotypes for Labrador retrievers are shown below.Genotype PhenotypeBBEe blackbbEe brownBbee yellow Two dogs, each with the genotype, BbEe, were crossed. What is the percentageprobability that their offspring will have yellow coat colour? (Record your answer as awhole number percentage)arrow_forwardThe white Leghorn breed of chickens is homozygous for the dominant allele C, which produces colored feathers. However, this breed is also homozygous for the dominant allele I of an independently assorting gene that inhibits coloration of the feathers. Consequently, Leghorn chickens have white feathers. The white Wyandotte breed of chickens has neither the allele for color nor the inhibitor of color; it is therefore genotypically cc ii. What are the F2 phenotypes and proportions expected from intercrossing the progeny of a white Leghorn hen and a white Wyandotte rooster?arrow_forward
- As seen in the photo, Labradors come in three colors-- black, brown and yellow. What is the genetic basis for these different coat colors? One gene produces melanin, a pigment which is deposited in the dog's fur and makes the color dark. With this gene, allele B (black) is dominant to allele b. Only in the case of a recessive homozygote (bb) will the dog's phenotype be brown. The regulatory gene is separate from the melanin gene but it acts as a switch, either turning the melanin gene on or turning it off. Allele E is dominant and allows for the melanin to be deposited in the dog's fur ("on" switch), but if the switch gene is a recessive homozygote, the melanin is blocked ("off" switch) and a yellow dog is the result! 1. Two other Labradors mate and produce puppies. Their genotypes are Bbee and BbEe. What color are each parent and what are the phenotypic rations of their offspring in the F1 Generation? Show your work with a Punnett square.arrow_forwardIn peaches fuzzy skin (F) is completely dominant to smooth, nectarine skin (f). The gland at the base of the leaves is controlled by a separate, unlinked locus. The gland in heterozygotes is round, while homozygotes with the Go allele have oval glands, and homozygotes with the the GN allele have no glands. A homozygous fuzzy, no-gland peach variety is bred to a smooth, oval-gland variety. The F1 offspring are interbred to produce the F2 generation. What fraction of the F2 offspring will be smooth with round glands? A) 3/16 B) 7/16 C) 4/16 D) 6/16 E) 9/16 F) 2/16 G) 12/16 H) 1/16arrow_forwardIn a species of plant, two genes control flower color. The red allele(R) is dominant to the white allele (r); the color-producing allele(C) is dominant to the non-color-producing allele (c). You suspectthat either an rr homozygote or a cc homozygote will producewhite flowers. In other words, rr is epistatic to C, and cc is epistatic to R. To test your hypothesis, you allow heterozygous plants(RrCc) to self-fertilize and count the offspring. You obtain the following data: 201 plants with red flowers and 144 with white flowers. Conduct a chi square analysis to see if your observed data areconsistent with your hypothesis.arrow_forward
- In chickens, comb shape is determined by alleles at two loci (R, r and P,p). A walnut comb is produced when at least one dominant allele R ispresent at one locus and at least one dominant allele P is present at asecond locus (genotype R_ P_). A rose comb is produced when at leastone dominant allele is present at the first locus and two recessive allelesare present at the second locus (genotype R_ pp). A pea comb isproduced when two recessive alleles are present at the first locus and atleast one dominant allele is present at the second (genotype rr P_). Iftwo recessive alleles are present at the first and at the second locus (rrpp), a single comb is produced. Progeny with what types of combs andin what proportions will result from the following crosses? a. RR PP × rr pp b. Rr Pp × rr pp c. Rr Pp × Rr Pp d. Rr pp × Rr pp e. Rr pp × rr Pp f. Rr pp × rr pparrow_forwardIn mice, the wild-type coat color, agouti (AA) [left mouse], is dominant to solid-colored, black fur (aa) [middle mouse]. However, a separate gene (C) is necessary for pigment production. A mouse that is homozygous for a recessive c allele at this locus is unable to produce pigment and is albino [right mouse] regardless of the allele present at locus A. Thus, the following genotypes are listed with their associated phenotypes: ~ A/A; C/C or A/A; C/c or A/a; C/C or A/a; C/c ==> "agouti" ~ a/a; C/C or a/a; C/c ==> "black" ~ A/A; c/c or A/a; c/c or a/a; c/c or a/a; c/c ==> "albino" This is an example of recessive epistasis, in which the recessive c allele "stands upon" the possible genotypes for the A gene (A/A, A/a, or a/a). If two agouti mice with the A/a; C/c genotype are mated, what is the expected phenotypic ratio in their offspring? A.9 albino, 4 agouti, 3 black B. 9 agouti, 4 albino, 3 black C.9 black, 4 albino, 3 agouti D.9 agouti, 4 black, 3 albinoarrow_forwardIn Drosophila, an allele causing vestigial wings is 12.5 mu awayfrom another allele that causes purple eyes. A third gene that affectsbody color has an allele that causes black body color. Thisthird gene is 18.5 mu away from the vestigial wings allele and 6mu away from the allele causing purple eyes. The alleles causingvestigial wings, purple eyes, and black body are all recessive.The dominant (wild-type) traits are long wings, red eyes, and graybody. A researcher crossed wild-type flies to flies with vestigialwings, purple eyes, and black bodies. All F1 flies were wild type.F1 female flies were then crossed to male flies with vestigial wings,purple eyes, and black bodies. If 1000 offspring were observed,what are the expected numbers of the following types of flies? long wings, red eyes, gray bodylong wings, purple eyes, gray bodylong wings, red eyes, black bodylong wings, purple eyes, black bodyshort wings, red eyes, gray bodyshort wings, purple eyes, gray bodyshort wings, red eyes,…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