In the early 20th century, the following information was discovered about comb shape in chickens. If a chicken had a dominant R allele and was homozygous recessive for the P gene, then the comb was rose-shaped. If a chicken had a dominant P allele and was homozygous recessive for the R gene, then the comb was pea-shaped. However, if a chicken had both a dominant P allele and a dominant Rallele, then the comb was walnut-shaped. Homozygous recessive alleles for both genes resulted in the single comb shape. The phenotypic expression of comb shape in chickens is the result of what phenomenon? * O Penetrance O Incomplete dominance O Codominance O Epistasis

In the early 20th century, the following information was discovered about comb shape in chickens. If a chicken had a dominant R allele and was homozygous recessive for the P gene, then the comb was rose-shaped. If a chicken had a dominant P allele and was homozygous recessive for the R gene, then the comb was pea-shaped. However, if a chicken had both a dominant P allele and a dominant Rallele, then the comb was walnut-shaped. Homozygous recessive alleles for both genes resulted in the single comb shape. The phenotypic expression of comb shape in chickens is the result of what phenomenon? * O Penetrance O Incomplete dominance O Codominance O Epistasis

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter15: Genomes And Genomics

Section: Chapter Questions

Problem 2QP: Hemophilia and color blindness are both recessive conditions caused by genes on the X chromosome. To...

See similar textbooks

Similar questions

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! Review the information on Labrador retrievers above. What are the phenotypic ratios of the F1 generation offspring of two dihybrids? Make sure to match the numbers with coat colors (e.g, which number in the ration goes with which color). Use a Punnett square to…
Among Native Americans, two types of earwax (cerumen) are seen, dry and sticky. A geneticist studied theinheritance of this trait by observing the types of offspring produced by different kinds of matings. Heobserved the following numbers:OffspringParents Number of mating pairs Sticky DrySticky × sticky 10 32 6Sticky × dry 8 21 9Dry × dry 12 0 42a. How is earwax type inherited?b. Why are no 3:1 or 1:1 ratios present in the datashown in the chart?
. In 1919, Calvin Bridges began studying an X-linkedrecessive mutation causing eosin-colored eyes inDrosophila. Within an otherwise true-breedingculture of eosin-eyed flies, he noticed rare variantsthat had much lighter cream-colored eyes. By intercrossing these variants, he was able to make a truebreeding cream-eyed stock. Bridges now crossedmales from this cream-eyed stock with true-breedingwild-type females. All the F1 progeny had red (wildtype) eyes. When F1 flies were intercrossed, the F2progeny were 104 females with red eyes, 52 maleswith red eyes, 44 males with eosin eyes, and14 males with cream eyes. Assume that thesenumbers represent an 8:4:3:1 ratio.a. Formulate a hypothesis to explain the F1 and F2results, assigning phenotypes to all possiblegenotypes.b. What do you predict in the F1 and F2 generations if the parental cross is between truebreeding eosin-eyed males and true-breedingcream-eyed females?c. What do you predict in the F1 and F2 generationsif the parental cross is…
In 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,…
Gene A controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, A, have sharp spines, whereas homozygous recessive aa cactuses have dull spines. At the same time, a second gene, N, determines whether cactuses have spines at all. Homozygous recessive nn cactuses have no spines at all. a) The relationship between genes A and N is an example of ________________ b) A cactus with sharp spines is crossed with a spineless cactus. All the offspring have spines but approximately half of the 100 offspring have dull spines and half have sharp spines. What are the genotypes of the parent cacti?
In Labrador retrievers, two genes determine fur color: the E gene and the B gene. Black fur (B) is dominant to brown fur (b). However, the presence of (ee) will overshadow and create a puppy with yellow fur. Create a Punnett square crossing 2 Labs that are heterozygous for both genes. Then color code your Punnett Square based on the resulting phenotypes. Don’t forget to take epistasis into account!
A mouse from a true-breeding population with normal gait was crossed to a mouse displaying an oddgait called dancing. The F1 animals all showednormal gait.a. If dancing is caused by homozygosity for the recessive allele of a single gene, what proportion ofthe F2 mice should be dancers?b. If mice must be homozygous for recessive allelesof each of two different genes to have the dancing phenotype, what proportion of the F2 shouldbe dancers if the two genes are unlinked?(Assume that all the mice in the populationwith normal gait were homozygous fordominant alleles.)c. When the F2 mice were obtained, 42 normal and8 dancers were seen. Use the chi-square test todetermine if these results better fit the one-genemodel from part (a) or the two-gene model frompart (b).
In chickens, a dominant hereditary abnormality (e.g., creepers) causes death when the genotype is homozygous (CC). The recessive condition (cc) at this locus produces a normal phenotype. Another gene locus with co dominant alleles is known to govern feather color such that the genotype FF = black, ff = splashed white, and Ff = blue. Also, a completely dominant gene W produces white skin. Yellow skin is produced by the homozygous genotype ww. QUESTIONS: In CcFfWw x ccffWw, what proportion of the offspring is: b.2 normal, white feathered, white skinned b.3 yellow skinned
In aliens, the genes A, B, C, D and E are dominant to their respective alleles a, b, c, d and e: A = one eye a = two eyes B = pointed ears b = round ears C = red skin c = green skin D = two antennae d = three antennae E = square head e = triangular head An alien with genotype AA bb Cc dd Ee marries an alien with genotype Aa Bb Cc Dd Ee. If the genes segregate independently, what is the probability that they will have a child with one eye, pointed ears, red skin, three antennae and a triangular head? A. 9/512 B. 9/128 C. 27/1024 D. 3/64
In genetics, the dash symbol (–) is a “wild card” that stands for either the dominant allele or the recessive allele; for example, A– means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect coat color in Duroc pigs. Each gene has two alleles, one of which is dominant for coat color. Genotypes of the form A– B– are red, those of the form A– bb and aa B– are sandy, and genotype aa bb is white. What ratio of red:sandy:white is expected from the cross Aa Bb x Aa Bb?
raccoons may have wide, medium-sized, or narrow bands around their tails. They may also havethe habit of washing all, or some of their food, or do not wash their food at all. a) assign genotypes to the phenotypes mentioned (see attached table) b. What mode of inheritance would most likely be exhibited by these traits if crosses were made? c. If two raccoons with medium-sized tail bands and have the habit of washing some of theirfoods will be crossed, what is the probability of having F1 raccoons with: c.1 wide tail bands that won’t wash any of their food? c.2 the same genotype as the parent raccoons? d. If a raccoon with a wide tail band that washes only some of its food is crossed with a raccoonwith a narrow tail band that doesn’t wash any food, what percentage of their offspring wouldbe medium-tailed and washes all its food? Show COMPLETE cross.
Attached earlobes in bats is a rare recessive trait. In the pedigree below, solid symbols represent "attached ear" (ae) and open symbols "unattached ear" (ae+) phenotypes. 2 II 3 4 5 II 1 5 6 IV What is the genotype of the male l-1, and which of the offspring in generation Il must be attached ear heterozygotes? а. ae+ / ae and Il-1; II-3; II-5 b. ae / ae and Il-1; Il-2; II-3; II-4; II-5; Il-6 С. ae+ / ae and II-1; II-5 d. ae+ / ae and none е. Not enough information to answer