Related Experiment Video
Updated: Aug 10, 2026
06:08
Genetic Engineering of Dictyostelium discoideum Cells Based on Selection and Growth on Bacteria
Published on: January 25, 2019
Formation of dicentrics with variable lengths in transformed cells
1Department of Biology, University of Nevada, Reno 89557-0015.
Cancer Genetics and Cytogenetics
|June 1, 1993
Summary
Dicentric chromosomes in transformed cells show variable lengths between centromeres due to sister chromatid reorganization. This process involves two breaks and nonreciprocal rejoining, supporting Revell
Area of Science:
- Cytogenetics
- Molecular Biology
- Cancer Research
Background:
- Dicentric chromosomes, characterized by two centromeres, are frequently observed in transformed and cancerous cells.
- Variations in the length of the intercentromeric region within dicentric chromosomes suggest underlying dynamic structural changes.
Purpose of the Study:
- To investigate the mechanism responsible for the observed length variations in the intercentromeric segment of dicentric chromosomes.
- To determine if these variations support existing hypotheses on chromosome instability and reorganization.
Main Methods:
- Analysis of dicentric chromosomes in transformed cell lines.
- Microscopic examination to assess variations in the intercentromeric region.
- Hypothesizing mechanisms of chromatid breaks and rejoining.
Main Results:
- Dicentric chromosomes exhibit significant length variations in the region between the two centromeres.
- The proximal centromere position remains consistent across observed dicentric chromosomes.
- Length changes are attributed to interchromatid reorganization involving sister chromatid exchange.
Conclusions:
- Interchromatid reorganization, involving two chromatid breaks and nonreciprocal rejoining, explains the length variability of the intercentromeric segment.
- These findings provide experimental support for Revell's hypothesis regarding chromosome instability and repair mechanisms.
Related Concept Videos
01:17Karyotyping
Describing the number and physical features of chromosomes can reveal abnormalities that underlie genetic diseases. This description is facilitated by special staining techniques that produce a particular banding pattern on each chromosome. State-of-the-art techniques make this approach even more powerful, enabling the detection of individual genes that cause disease.A Simple Chromosome Staining Technique Provides Valuable Scientific InsightSome genetic diseases can be detected by looking at...
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...
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:15Condensins
Condensins are large protein complexes that use ATP to fuel the assembly of chromosomes during mitosis. They transform the tangled, shapeless mass of post-interphase DNA into individualized chromosomes by compacting, organizing, and segregating chromosomal DNA.
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
02:25Centrosome Duplication
The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...
02:33Distribution of Cytoplasmic Content
Cytokinesis segregates a cell’s chromosomes and organelles into its daughter cells. Organelles divide and grow prior to cell division but cannot be synthesized de novo; therefore, cells must receive at least one copy of each organelle to survive. Currently, many of the details of how the organelles are distributed are not yet fully elucidated.
Distribution of cytoplasmic determinants
The cytoplasm contains various organelles, as well as salts, proteins, and water. The distribution of small...
Distribution of cytoplasmic determinants
The cytoplasm contains various organelles, as well as salts, proteins, and water. The distribution of small...