
Concept explainers
One of the autosomal loci controlling eye color in fruit flies has two alleles: one for brown eyes and the other for red eyes. Fruit flies from a true-breeding line with brown eyes were crossed with flies from a true-breeding line with red eyes. The F1 flies had red eyes. What conclusion can be drawn from this experiment? (a) these alleles underwent independent assortment (b) these alleles underwent segregation (c) these genes are X-linked (d) the allele for red eyes is dominant to the allele for brown eyes (e) all the preceding are true

Introduction: Locus (pl:loci) is the specific location of the gene in the chromosome. Alleles are variants of a gene. The allele that masks the expression of the other allele in heterozygous form is called the dominant allele.
Answer to Problem 1TYU
Correct answer: When fruits flies of true-breeding line with brown eyes are crossed with fruits flies of true-breeding line with red eyes, the F1 had red eyes that show that the allele for red eyes is dominant to the allele for brown eyes. Therefore, option (d) is correct.
Explanation of Solution
Reason for the correct answer.
When true breeding parents are crossed where one parent is homozygous for one allele and the other parent is homozygous for another allele, the trait expressed in the F1 generation is the dominant allele. When applying the above principle for the given question, where fruits flies of true-breeding line with brown eyes are crossed with fruits flies of true-breeding line with red eyes, the F1 will have red eyes. This shows that the allele for red eyes is dominant to the allele for brown eyes.
Option (d) is given as “the allele for red eyes is dominant to the allele for brown eyes”.
When fruits flies of true-breeding line with brown eyes are crossed with fruits flies of true-breeding line with red eyes, the F1 will have red eyes that show that the allele for red eyes is dominant to the allele for brown eyes. Therefore, option (d) is correct.
Reasons for the incorrect statements.
Option (a) is given as “these alleles underwent independent assortment”.
Independent assortment can be explained with two traits only. Here, only one trait is mentioned, that is eye color, therefore, they can show only segregation, not independent assortment. Hence, option (a) is incorrect.
Option (b) is given as “these alleles underwent segregation”.
This option is correct, yet the most suitable option will be option (d) as the law of segregation has proved right for single traits. This experiment reveals the dominant allele more than segregation. Hence, option (b) is incorrect.
Option (c) is given as “these genes are X-linked”.
The question mentions that these alleles are present in autosomal loci and therefore, they cannot be X-linked. Hence, option (c) is incorrect.
Option (e) is given as “all the preceding are true”.
Option (d) is the most suitable answer followed by option (b). The other options are incorrect. Hence, option (e) is incorrect.
Hence, options (a), (b), (c), and (e) are incorrect.
When fruits flies of true-breeding line with brown eyes are crossed with fruits flies of true-breeding line with red eyes, the F1 will have red eyes that show that the allele for red eyes is dominant over the allele for brown eyes.
Want to see more full solutions like this?
Chapter 11 Solutions
Mindtap Biology, 1 Term (6 Months) Printed Access Card For Solomon/martin/martin/berg's Biology, 11th
- Not part of a graded assignment, from a past midtermarrow_forwardNoggin mutation: The mouse, one of the phenotypic consequences of Noggin mutationis mispatterning of the spinal cord, in the posterior region of the mouse embryo, suchthat in the hindlimb region the more ventral fates are lost, and the dorsal Pax3 domain isexpanded. (this experiment is not in the lectures).a. Hypothesis for why: What would be your hypothesis for why the ventral fatesare lost and dorsal fates expanded? Include in your answer the words notochord,BMP, SHH and either (or both of) surface ectoderm or lateral plate mesodermarrow_forwardNot part of a graded assignment, from a past midtermarrow_forward
- Explain in a flowcharts organazing the words down below: genetics Chromosomes Inheritance DNA & Genes Mutations Proteinsarrow_forwardplease helparrow_forwardWhat does the heavy dark line along collecting duct tell us about water reabsorption in this individual at this time? What does the heavy dark line along collecting duct tell us about ADH secretion in this individual at this time?arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage LearningHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage LearningBiology (MindTap Course List)BiologyISBN:9781337392938Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. BergPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College





