Heterochrony is
a. the alteration of the spatial pattern of gene expression.
b. a change in the relative position of a body part.
c. a change in the relative timing of developmental events.
d. a change in a signaling pathway.
Introduction:
Changes in the development, contribute towards the evolution. The species which are closely related differ from each other because of the genetic changes. These genetic changes lead to differences in their developmental pattern, which result in producing different phenotype. The types of these developmental changes include homeosis and heterochrony.
Answer to Problem 1U
Correct answer:
The alterations in the timing of developmental events due to genetic changes are called heterochrony. Therefore, option c. is correct.
Explanation of Solution
Reason for the correct statement:
When the transcription factors are modified during evolution, they bring changes in the gene function. These changes in genes bring alterations in the timing of developmental events. Such modifications are known as heterochrony.
Option c. is given as "a change in the relative timing of developmental events".
As, “in heterochronic mutations, alterations in the timing of developmental events take place as a result of evolutionary changes in the genes”, is the right answer.
Hence, option c. is correct.
Reasons for the incorrect statements:
Option a. is given as “the alteration of the spatial pattern of gene expression”.
The alterations in the spatial pattern of gene expression, is a type of homeosis. So, it is a wrong answer.
Option b. is given as “a change in the relative position of a body part.”
Change in the relative position of a body part is a type of homeotic mutation, which does not produce a phenotype which is viable. So, it is a wrong answer.
Option d. is given as “a change in the signaling pathway”.
Change in the signaling pathway, results in the appearance of a homeotic phenotype. So, it is a wrong answer.
Hence, options a, b and d are incorrect.
A change in the relative timing of developmental events is known as heterochrony.
Want to see more full solutions like this?
Chapter 25 Solutions
Biology
- What is NOT an example of antagonistic pleiotropy? A. Developmental genes that code for greater or fewer than seven cervical vertebrae have negative fitness costs. B. Genes that create insect breathing tubes cause decreased production of growth hormones. C. Mutations that confer resistance to Bt also make insects more vulnerable to natural plant defensive chemicals. D. Two of the three choices are correct.arrow_forwardWhich of the following statements is incorrect? a. Some gene expression patterns can be passed to an individual's offspring. b. Expression of a master regulator triggers a gene expression cascade. c. X chromosome inactivation is necessary for normal development of male mammals.arrow_forwardWhat piece of a transcript is utilized to localize the mRNA and why is this critical to development? a. 3'UTR; protein gradients have a large influence on gene expression of cells b. 5'UTR; protein gradients have a large influence on gene expression in cells c. the promoter; it has a large influence on protein production within a cell d. The TATA box; it has a large influence on protein production within a cellarrow_forward
- The FOXP gene strongly affects what else, in addition to brain development? A. The stomach and intestines B. The pituitary and adrenal glands C. The jaw and throat D. Blood pressure and heart ratearrow_forwardWhat is the phenotype of the gnom mutant? A. Loss of cell fate B. Lack of cell-cell communication C. loss of embryo polarity D. Failure of cell differentiationarrow_forwardSignal transduction pathways are important mechanisms for cell-to-cell communication in multicellular organisms. How do the target cells typically respond when they receive signals from neighboring cells during very early stages of embryo development? A. The target cells move to one of the poles to establish the anterior-posterior body axis. B. The target cells undergo changes in gene expression, sending them down a specific developmental path. C. The target cells stop dividing so the neighboring cells have time to get to the same stage of development. D. The target cells activate a collection of miRNAs to accelerate transcription and cell division.arrow_forward
- BRCA1 is a gene that codes for a tumor suppressor protein. If a person inherits a mutation in BRCA1, it greatly increases his or her risk of developing breast cancer. Are the cancer-causing mutations in the BRCA1 gene more likely to: A) not affect expression of the gene B) increase expression of the gene C) decrease expression of the genearrow_forwardA nerve cell and a skin cell from the same person have Group of answer choices A. different gene expression B. different versions of genes C. same gene expression D. none of the above E. different genesarrow_forwardWhich of the following best describes a gene that codes for a tumor-suppressor protein? a. One that helps to prevent progression through the cell cycle. b. One that helps prevent apoptosis. c. One that codes for a DNA repair enzyme. d. One that supports part of a growth factor signaling pathway.arrow_forward
- Which statement about Hox genes is false? a. They are expressed in similar patterns in the embryos of both mice and flies. b. They include a conserved region of base pairs called the homeobox. c. They are arranged in similar clusters of genes in both mice and flies. d. They are part of the so-called genetic toolkit. e. Because of their important functional roles, they evolved rapidly in both mammals and flies.arrow_forwardSome uninformed people might argue that studying the development of an obscure little fish like the threespine stickleback is a waste of time and money. Why would biologists study the genes that control development in stickleback fish? Give some reasonsarrow_forwardPropose a hypothesis that could explain the following observation. A graduate student performing studies on mutations in drosophila (fruit flies) discovered a strain of flies with a silent mutation in the gene controlling the shape of the wings. Further investigation has shown that this mutation is lethal in flies who are homozygote. Flies that are homozygote wild type or heterozygote can develop and are able to survive.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