Chromosome Squash Technique
Chromosome Squash Technique - Related Videos
06:37
Preparation of Drosophila Polytene Chromosome Squashes for Antibody Labeling
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Cited by 28 •
2010
This video protocol illustrates the squash technique used in the Johansen laboratory to prepare Drosophila polytene chromosomes for antibody labeling.
11:36
Simple Method for Fluorescence DNA In Situ Hybridization to Squashed Chromosomes
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Cited by 55 •
2015
Here, we present a simple method for performing fluorescence DNA in situ hybridization (DNA ISH) to visualize repetitive heterochromatic sequences on slide-mounted chromosomes. The method requires minimal reagents and it is versatile for use with short or long probes, different tissues, and detection with fluorescence or non-fluorescence-based signals.
09:57
2D and 3D Chromosome Painting in Malaria Mosquitoes
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Cited by 8 •
2014
Chromosome painting is a useful method for studying organization of the cell nucleus and evolution of the karyotype. Here, we demonstrate an approach to isolate and amplify specific regions of interest from single polytene chromosomes that are subsequently used for two- and three-dimensional fluorescent in situ hybridization (FISH).
09:40
A Seminiferous Tubule Squash Technique for the Cytological Analysis of Spermatogenesis Using the Mouse Model
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Cited by 30 •
2018
The goal of this tubule squash technique is to rapidly assess cytological features of developing mouse spermatocytes while preserving cellular integrity. This method allows for the study of all stages of spermatogenesis, and can be easily implemented alongside other biochemical and molecular biological approaches for the study of mouse meiosis.
09:00
Fluorescent in situ Hybridization on Mitotic Chromosomes of Mosquitoes
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Cited by 41 •
2012
Among the three mosquito genera, namely Anopheles, Aedes, and Culex, physical genome mapping techniques were established only for Anopheles, whose members possess readable polytene chromosomes. For the genera of Aedes and Culex, however, cytogenetic mapping remains challenging because of the poor quality of polytene chromosomes. Here we present a universal protocol for obtaining high-quality preparations of mitotic chromosomes and an optimized FISH protocol for all three genera of mosquitoes.
FAQs
Actively dividing tissue contains cells passing through mitosis, when chromosomes become condensed and suitable for microscopic examination. This timing allows the preparation to capture distinct mitotic stages and supports observations of chromosome number, structure, and behavior. Using nondividing tissue would not provide the same opportunity to examine chromosomes in these visible, organized stages.
Fixation is performed before compression so the tissue can undergo the remaining preparation steps while preserving the cellular material being examined. Staining then makes the chromosomes visible under a light microscope, allowing researchers to distinguish their condensed forms from surrounding cell contents. Together, these steps prepare the sample for clearer cytological analysis.
Gentle compression separates neighboring cells and spreads their condensed chromosomes across a single optical plane. This arrangement reduces overlap and makes individual chromosome groups easier to inspect through the microscope. The pressure must be controlled because the purpose is to distribute the cells and chromosomes for observation, not simply to flatten the tissue indiscriminately.
The preparation can reveal mitotic stages by capturing cells whose chromosomes are condensed and arranged in recognizable patterns during division. Examining these stages helps researchers study chromosome behavior as well as chromosome number and structure. The resulting slide therefore provides a cytological view of cell division rather than only a general image of the tissue.
A typical workflow begins with actively dividing tissue, followed by fixation and staining. The prepared tissue is then placed between a microscope slide and coverslip and gently compressed. After the cells and chromosomes spread into a single optical plane, the slide is examined with a light microscope to assess mitotic stages, chromosome number, or visible structural features.
Chromosome squash preparations can support estimates of chromosome number and observations of chromosome structure and behavior. They also allow researchers to identify abnormalities visible in the prepared cells. Because the chromosomes are examined within cells undergoing mitosis, the method connects chromosome features with specific stages of cell division and provides useful cytological evidence.
The technique is used in cytogenetics, taxonomy, and investigations of cell division, as well as in biology education. Its applications extend across plants, animals, and other organisms, allowing chromosome features to contribute to organismal comparisons and cellular studies. In teaching, prepared slides also provide a direct way to examine mitotic stages with a light microscope.
Its value comes from combining chromosome visibility with observations of number, structure, and mitotic behavior in prepared cells. Cytogenetic studies can use these features to examine abnormalities, while taxonomic work can use chromosome information when comparing organisms. The same preparation also supports cell-division research, giving the method relevance across several areas of biology.