Developmental Biology
Developmental Biology
11th Edition
ISBN: 9781605354705
Author: Scott F. Gilbert, Michael J. F. Barresi
Publisher: Sinauer Associates is an imprint of Oxford University Press
bartleby

Concept explainers

bartleby

Videos

Question
Book Icon
Chapter 9, Problem 1DQ
Summary Introduction

To review:

The reason for not observing the extra set of limbs in humans as a result of homeotic mutations, as observed in the case of Drosophila.

Introduction:

In case of Drosophila, the homeotic selector genes regulate the characteristic structures of each segment. Most of the homeotic genes are present in two regions of chromosome III. Antennapedia complex is the first region and bithorax complex is the second region. These genes are not unique to fruit fly, many other organisms also contains these genes. The homeotic mutants of Drosophila leads to bizarre phenotypes, for example, a fly with four wings is a result of deletion of Ultrabithorax gene. But in case of humans, the homeotic mutation leads to a number of abnormalities, instead of emergence of extra limbs.

Expert Solution & Answer
Check Mark

Explanation of Solution

The homeotic genes are always considered as powerful developmental genes which are preserved and modified along with the evolutionary line. These genes regulate the identity of the body segments along the head-tail axis. The mutation in these genes defects the signalling related to the formation of body parts. The beginning of body parts specification is done in the early embryo development. In humans, the homeotic mutation cause few diseases like lymphomas, in which white blood cells follows wrong lineage, DiGeorge syndrome, lack of thymus and parathyroid, abnormality in nose, ear, mouth and legs.

The mutation in Hox D13 leads to a genetic disorder known as synpolydactyly, in which extra fingers or toes are present in the fused form.

Conclusion

Thus it is concluded that homeotic genes play an important role in regulating the structural parts of body in different organisms including plants. The effect of mutation is not exactly same in all, in case of humans these mutations results a number of abnormalities like synpolydactyly (fused extra fingers or toes), DiGeorge syndrome, etc.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Structures REVIEW QUESTIONS The table below compares structures found in bacterial (prokaryotic) cells with those found in animal and plant (eukaryotic) cells. Indicate by writing Yes or No if the structure is present in the cell types. Cell Wall Cell Membrane Nuclear Envelope Chromosome (DNA) Mitochondria Cytosol Ribosome Lysosome Cytoskeleton Plastids Endoplasmic Reticulum Central Vacuole Peroxisome Golgi Complex LABORATORY 4 Centrosome Cilia Section Bacterial Cell Animal Cell Plant Cell
Task # 4 Genotypes and Phenotypes: The Mc1r gene is located on chromosome #16 in mice. Mice are diploid so every somatic cell has two copies of the Mc1r gene. Since there are two Mc1r alleles there are three possible genotypes: MM, Mm and mm. M-dark pigment m=less pigment Parental generation: an inland mouse (MM) mates with a beach mouse (mm) A. What is the genotype of the F1 offspring? B. If this trait exhibits simple (Mendelian) dominance, circle the phenotype expected for the F1 fur color: dark pigment / medium pigment / less pigment Observed phenotype: F1 actually have medium pigment. Initially this looks like blending, but it is not. M and m are discrete units. This observation does not disprove Mendel's First Law which holds true for the genotypes. Individuals with genotype Mm produce more pigment than individuals with genotype mm and less than individuals with genotype MM. and show the gametes and offspring C. Write the F1 x F1 cross in a Punnett square below. X D. What…
Questions: 1. How does the genetic code determine the expression of heritable traits in an organism? 2. What are the mechanisms of gene regulation that control the expression of heritable traits? 3. What are the functions of DNA segments that do not code for proteins?

Chapter 9 Solutions

Developmental Biology

Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Comprehensive Medical Assisting: Administrative a...
Nursing
ISBN:9781305964792
Author:Wilburta Q. Lindh, Carol D. Tamparo, Barbara M. Dahl, Julie Morris, Cindy Correa
Publisher:Cengage Learning
Text book image
Biology (MindTap Course List)
Biology
ISBN:9781337392938
Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:Cengage Learning
Text book image
Biology: The Dynamic Science (MindTap Course List)
Biology
ISBN:9781305389892
Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan
Publisher:Cengage Learning
Mitochondrial mutations; Author: Useful Genetics;https://www.youtube.com/watch?v=GvgXe-3RJeU;License: CC-BY