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more than 2 weeks ago
Fluorescence in situ hybridization (FISH) is a molecular biology technique used to detect and localize the presence or absence of specific DNA sequences on chromosomes. In FISH, a fluorescently labeled DNA probe is hybridized to the target DNA sequence in fixed cells or tissue samples. The probe binds specifically to the complementary sequence, allowing researchers to visualize the location of the target sequence under a fluorescence microscope. FISH is commonly used in cytogenetics to detect chromosomal abnormalities, gene mapping, and studying gene expression patterns in cells.
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Google Gemini AI
more than 2 weeks ago
Definition:
Fluorescence in situ hybridization (FISH) is a cytogenetic technique used to detect and localize specific DNA sequences within chromosomes.
Principle:
FISH involves the use of DNA probes that are complementary to the target DNA sequence. These probes are labeled with fluorescent molecules, allowing them to be visualized under a fluorescent microscope.
Procedure:
1. Sample Preparation: Cells are collected and spread on a glass slide or deposited in a well.
2. Fixation: Cells are fixed to preserve their structure.
3. Permeabilization: Cell membranes are permeabilized to allow the probes to access the DNA.
4. Hybridization: Labeled probes are added to the sample and allowed to hybridize to their complementary DNA sequences on the chromosomes.
5. Washing: Excess probes are removed by washing.
6. Visualization: The slide is observed under a fluorescent microscope to detect the fluorescent signals.
Applications:
FISH has numerous applications, including:
- Chromosome identification: Identifying specific chromosomes or chromosome abnormalities, such as translocations or deletions.
- Gene mapping: Localizing genes to specific chromosomes or regions within chromosomes.
- Cancer diagnosis and prognosis: Detecting chromosomal rearrangements or gene amplifications associated with certain cancers.
- Prenatal diagnosis: Detecting genetic abnormalities in fetal cells.
- Forensic science: Identifying individuals or samples based on their DNA profiles.
Advantages:
- High specificity and sensitivity
- Allows simultaneous visualization of multiple target sequences
- Can be used on fixed or interphase cells
- Can provide information about gene expression patterns
Limitations:
- Requires specialized equipment and expertise
- Can be expensive and time-consuming
- May not be sensitive enough to detect small genomic changes
Fluorescence in situ hybridization (FISH) is a cytogenetic technique used to detect and localize specific DNA sequences within chromosomes.
Principle:
FISH involves the use of DNA probes that are complementary to the target DNA sequence. These probes are labeled with fluorescent molecules, allowing them to be visualized under a fluorescent microscope.
Procedure:
1. Sample Preparation: Cells are collected and spread on a glass slide or deposited in a well.
2. Fixation: Cells are fixed to preserve their structure.
3. Permeabilization: Cell membranes are permeabilized to allow the probes to access the DNA.
4. Hybridization: Labeled probes are added to the sample and allowed to hybridize to their complementary DNA sequences on the chromosomes.
5. Washing: Excess probes are removed by washing.
6. Visualization: The slide is observed under a fluorescent microscope to detect the fluorescent signals.
Applications:
FISH has numerous applications, including:
- Chromosome identification: Identifying specific chromosomes or chromosome abnormalities, such as translocations or deletions.
- Gene mapping: Localizing genes to specific chromosomes or regions within chromosomes.
- Cancer diagnosis and prognosis: Detecting chromosomal rearrangements or gene amplifications associated with certain cancers.
- Prenatal diagnosis: Detecting genetic abnormalities in fetal cells.
- Forensic science: Identifying individuals or samples based on their DNA profiles.
Advantages:
- High specificity and sensitivity
- Allows simultaneous visualization of multiple target sequences
- Can be used on fixed or interphase cells
- Can provide information about gene expression patterns
Limitations:
- Requires specialized equipment and expertise
- Can be expensive and time-consuming
- May not be sensitive enough to detect small genomic changes
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