Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 18 - Developmental Genetics
Sanders - Genetic Analysis: An Integrated Approach 3rd Edition
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
All textbooksSanders 3rd EditionCh. 18 - Developmental GeneticsProblem 24a
Chapter 18, Problem 24a

Homeotic genes are thought to regulate each other. What aspect of the phenotype of apetala2 agamous double mutants indicates that these two genes act antagonistically?

Verified step by step guidance
1
Understand the role of homeotic genes: Homeotic genes are responsible for determining the identity of structures in specific regions of an organism. In plants, genes like APETALA2 (AP2) and AGAMOUS (AG) are involved in floral organ development.
Define antagonistic gene interaction: When two genes act antagonistically, it means they have opposing effects on a particular developmental process or phenotype. This can result in a balance or regulation of the final outcome.
Examine the phenotype of single mutants: APETALA2 mutants typically show defects in sepals and petals, while AGAMOUS mutants show defects in reproductive organs like stamens and carpels. This provides insight into their individual roles in floral organ development.
Analyze the phenotype of double mutants: In apetala2 agamous double mutants, the phenotype may show a disruption in the balance between the effects of AP2 and AG. For example, the absence of both genes could lead to a loss of floral organ identity or an abnormal arrangement of organs, indicating their opposing roles in regulating floral development.
Conclude the antagonistic relationship: The specific aspect of the phenotype that demonstrates antagonism is the way the double mutant phenotype differs from the single mutants. This suggests that APETALA2 and AGAMOUS counteract each other to maintain proper floral organ identity and development.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
3m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Homeotic Genes

Homeotic genes are a group of regulatory genes that control the development of anatomical structures in various organisms. They play a crucial role in determining the identity of body parts during embryonic development. In plants, these genes can influence flower morphology and organ identity, making them essential for understanding phenotypic variations.
Recommended video:
Guided course
11:19
Segmentation Genes

Antagonistic Gene Interaction

Antagonistic gene interaction occurs when two genes exert opposing effects on a particular trait or phenotype. In the context of the apetala2 and agamous genes, this means that the presence or activity of one gene can suppress or negate the effects of the other, leading to distinct phenotypic outcomes in double mutants. Understanding this interaction is key to deciphering the complex regulatory networks in developmental biology.
Recommended video:
Guided course
07:56
Interacting Genes Overview

Phenotypic Analysis

Phenotypic analysis involves studying the observable characteristics or traits of an organism, which result from the interaction of its genotype with the environment. In the case of apetala2 agamous double mutants, examining the resulting flower structures can reveal how these genes interact and influence development. Identifying specific phenotypic traits helps in understanding the functional roles of the genes involved.
Recommended video:
Guided course
02:48
Chi Square Analysis
Related Practice
Textbook Question

Three-spined stickleback fish live in lakes formed when the last ice age ended 10,000 to 15,000 years ago. In lakes where the sticklebacks are prey for larger fish, they develop 35 bony plates along their body as armor. In contrast, sticklebacks in lakes where there are no predators develop only a few or no bony plates. In crosses between fish of the two different morphologies, the lack of bony armor segregates as a recessive trait that maps to the ectodermal dysplasin (Eda) gene. Comparisons between the Eda-coding regions of the armored and nonarmored fish revealed no differences. How can you explain this result?

444
views
Textbook Question

Three-spined stickleback fish live in lakes formed when the last ice age ended 10,000 to 15,000 years ago. In lakes where the sticklebacks are prey for larger fish, they develop 35 bony plates along their body as armor. In contrast, sticklebacks in lakes where there are no predators develop only a few or no bony plates. Loss-of-function mutations in the coding region of the homologous gene in humans result in loss of hair, teeth, and sweat glands, as in the toothless men of Sind (India). What does this suggest about hair, teeth, and sweat glands in humans?

561
views
Textbook Question

The flowering jungle plant Lacandonia schismatica, discovered in southern Mexico, has a unique floral structure. Petal-like organs are in the outer whorls surrounding a number of carpels, and stamens are in the center of the flower. Closely related species are dioecious; female plants bear flowers that resemble those of Lacandonia, but without the central stamens. What type of mutation could have resulted in the evolution of Lacandonia flowers?

408
views
Textbook Question

Homeotic genes are thought to regulate each other. Are similar interactions observed between Hox genes?

494
views
Textbook Question

Dipterans (two-winged insects) are thought to have evolved from a four-winged ancestor that had wings on both T2 and T3 thoracic segments, as in extant butterflies and dragonflies. Describe an evolutionary scenario for the evolution of dipterans from four-winged ancestors. What types of mutations could lead to a butterfly developing with only two wings?

480
views
Textbook Question

Basidiomycota is a monophyletic group of fungi that includes most of the common mushrooms. You are interested in the development of the body plan of mushrooms. How would you identify the genes required for patterning during mushroom development?

602
views