Concept explainers
Suppose a polygenic system for producing color in ker-nels of a grain is controlled by three additive genes, G, M, and T. There are two alleles of each gene, GI and 02, MI and M2, and T1 and 72. The phenotypic effects of the three genotypes of the G gene are GIG, = 6 units of color, G1G2 = 3 units of color, and G2G2 = 1 unit of color. The phenotypic effects for genes M and T are similar, giving the phenotype of a plant with the genotype GIGIMIMITITI a total of 18 units of color and a plant with the genotype G2G2M2M2T2T2 a total of 3 units of color.
a) How many units of color are found in trihybrid plants?
b) Two trihybrid plants are mated. What is the expected proportion of progeny plants displaying 9 units of color? Explain your answer.
c) Suppose that instead of an additive genetic system, kernel-color determination in this organism is a thresh-old system. The appearance of color in kernels requires nine or more units of color; otherwise, kernels have no color and appear white. In other words, plants whose
d) Assuming the threshold model applies to this kernel-color system, what proportion of the progeny of the cross GIG2M1M2T2T2 x G 1 G2A/1/1/2Ti T2 do you expect to display colored kernels?
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Chapter 21 Solutions
GENETIC ANALYSIS: AN INTEG. APP. W/MAS
- Suppose a mutant fruit fly with blue eyes was recently discovered. It is later determined that the blue eye trait is recessive to the wild-type red eye trait. What is the most common way to represent the mutant and wild-type alleles?. Choices are Mutant: Bl, bl Wild-type: Bl+ , re, bl+, or wtarrow_forwardPlease solve this problem using the test cross branch diagram without a punnet square.arrow_forwardGive typed explanation In pea plants, the tall allele (T) is dominant to the dwarf allele (t) and the yellow pea color allele (Y) is dominant to the green pea color allele (y). Cross TtYy with Ttyy. What would be the genotype and phenotype ratios in their offspring? (Please include the gametes produced by each parent.)arrow_forward
- Give typing answer with explanation and conclusionarrow_forwardIn rabbits, white coat color (CW) and black coat color (CB) are codominant, and both of these alleles are dominant over albino (c); heterozygotes (CWCB) are spotted. Predict the genotypes and phenotypes of the offspring from a heterozygous black-coated rabbit and a homozygous white-coated rabbit.arrow_forwardDominant and recessive alleles of a gene in garden peas, G and g, cause seeds to be yellow and green, respectively. Dominant and recessive alleles, F and f, of another gene cause seeds to be spotted or not with violet color, respectively. A plant of genotype GGFF is crossed with a plant of genotype ggff, and the F1 are allowed to self-fertilize. The phenotypes and numbers of F2 progeny are shown below: Phenotype of F2 Number yellow, spotted 89 green, spotted 31 yellow, not spotted 29 green, not spotted 11 Are the G,g and F,f genes linked?arrow_forward
- Y = yellow, y = green; R = round seed, r = wrinkled seed %3D An individual has the genotype YYRR and has offspring with an individual with the genotype yyrr. If the genes are both expressed with complete dominance, then what phenotype will all the offspring have? Yellow and Wrinkled Yellow and Round Green and Round Green and Wrinkledarrow_forwardtrue for false? 1a) In Drosophila flies, there are wing shapes such as curly, apterous, miniature and others. These would be considered continuous traits (as opposed to discontinuous traits). 1b) The reason we assess the narrow sense heritability is because there are hidden genetic components that are simply too difficult to include in the calculation of VG 1c) You can figure out the heritability of a trait if you compare the variation of the trait in a clonal population of organisms to a wild type (heterogeneous) population.arrow_forwardUse the following information to answer the next question. A Venn Diagram Showing the Relationship Between Oogenesis and Spermatogeneis. Oogenesis 1 NOTE: Similarities are represented by area 2. Differences are represented by areas 1 or 3. Match the numbered regions with the descriptions below. Spermatogenesis 3 Four viable gametes produced: Occurs in gonads: Daughter cells equal in size Unequal cytoplasmic division ▶arrow_forward
- Shown in the pictures below are the degrees of dominance in the inheritance of flower color in some plants. *Based on the phenotypes (or maybe genotype), differentiate between complete dominance, incomplete dominance, and codominance. Be able to discuss the difference briefly but concisely. You may also refer to the definition.arrow_forwardSuppose two independently assorting genes are involved in the pathway that determines fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store. At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for a colored squash. At the second locus, the allele Y codes for a dominant yellow phenotype, and the allele y codes for a recessive green phenotype. The phenotypes from the first locus will always mask the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis. A dihybrid squash, Ww Yy, is selfed and produces 160 offspring. How many offspring are expected to have the white, yellow, and green phenotypes? number of white offspring: number of yellow offspring: number of green offspring:arrow_forwardSuppose two independently assorting genes are involved in the pathway that determines fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store. At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for a colored squash. At the second locus, the allele Y codes for a dominant yellow phenotype, and the allele y codes for a recessive green phenotype. The phenotypes from the first locus will always mask the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis. A dihybrid squash, Ww Yy, is selfed and produces 160160 offspring. How many offspring are expected to have the white, yellow, and green phenotypes?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College