Related Experiment Video
Updated: Jul 15, 2026
11:48
Grafting of Beads into Developing Chicken Embryo Limbs to Identify Signal Transduction Pathways Affecting Gene Expression
Published on: January 17, 2016
Limb development in diplopodia4: a polydactylous mutation in the chicken
The Journal of Experimental Zoology
|March 1, 1975
Summary
The diplopodia4 mutation in chickens causes limb polydactylism by affecting mesoderm, leading to thickened ectodermal ridges and extra digits. This genetic lesion impacts limb development without altering the zone of polarizing activity.
Area of Science:
- Developmental biology
- Genetics
- Chicken embryo development
Background:
- Polydactylism is a congenital anomaly characterized by supernumerary digits.
- The diplopodia4 mutation in chickens provides a model for studying limb development.
- Limb development involves complex interactions between mesoderm and ectoderm, regulated by signaling centers like the zone of polarizing activity.
Purpose of the Study:
- To investigate the cellular and molecular basis of the diplopodia4 mutation in chicken limb development.
- To determine the primary tissue affected by the diplopodia4 mutation.
- To assess the role of the zone of polarizing activity in the polydactylous phenotype.
Main Methods:
- Analysis of chicken embryos with the diplopodia4 mutation.
- Histological examination of limb-bud development.
- Assessment of ectodermal ridge thickening and outgrowth.
- Evaluation of the zone of polarizing activity's function and distribution.
Main Results:
- The genetic lesion in diplopodia4 primarily affects the mesoderm, with secondary effects on the ectoderm.
- Mutant mesenchyme induces thickening of the ectodermal ridge, resulting in preaxial polydactylism.
- The zone of polarizing activity in diplopodia4 limb-buds exhibits normal activity and distribution.
- Supernumerary limb outgrowth in mutants appears to stem from enhanced signaling from the polarizing zone.
Conclusions:
- The diplopodia4 mutation disrupts normal limb patterning by altering mesodermal-ectodermal interactions.
- The primary defect lies within the mesoderm, influencing ectodermal ridge development and digit formation.
- The zone of polarizing activity is not the primary cause of the polydactylism in this mutation, but its signaling may be modulated.
More Related Videos
08:08Chicken Recombinant Limbs Assay to Understand Morphogenesis, Patterning, and Early Steps in Cell Differentiation
Published on: January 12, 2022
06:49Analysis of Cell Differentiation, Morphogenesis, and Patterning During Chicken Embryogenesis Using the Soaked-Bead Assay
Published on: January 12, 2022
Related Concept Videos
01:51Lampbrush Chromosomes
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
02:04Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...
02:41Lethal Alleles
Agouti: A Lethal Allele
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
00:49Complementation Tests
A complementation test is a simple cross to identify whether the two mutations are located on the same gene or different genes. It was first performed by Edward Lewis in the 1940s while working on fruit flies. He developed the test to identify the location and arrangement of different mutations on chromosomes.
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
01:07Development of the Limb Synovial Joints
Joints form during embryonic development in conjunction with the formation and growth of the associated bones. The embryonic tissue that gives rise to all bones, cartilage, and connective tissues of the body is called mesenchyme.
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...
The mesenchymal stem cells differentiate into chondrocytes that form the hyaline cartilage, and later the cartilaginous model of the bone. This model further transforms into a bone. This process is known as endochondral ossification.
During development, the limbs...