Which of the following tests is used to differentiate the chromosome of normal and cancer cells?
**Core Concept**
The question pertains to the field of cytogenetics, specifically the techniques used to analyze and differentiate chromosomes in normal and cancer cells. The underlying principle being tested involves the use of specific methods to identify chromosomal abnormalities associated with malignancy.
**Why the Correct Answer is Right**
The correct answer is **Karyotyping**. Karyotyping involves the process of analyzing the chromosomes in a cell to identify any abnormalities, such as deletions, duplications, or translocations. This technique is commonly used in cancer diagnosis to identify specific chromosomal changes that are associated with particular types of cancer. For example, the Philadelphia chromosome, which results from a translocation between chromosomes 9 and 22, is a hallmark of chronic myeloid leukemia.
**Why Each Wrong Option is Incorrect**
**Option A:** **Fluorescence In Situ Hybridization (FISH)** is a molecular cytogenetic technique used to detect and locate a specific DNA sequence on a chromosome. While FISH can be used to identify chromosomal abnormalities, it is not the primary method used to differentiate the chromosomes of normal and cancer cells.
**Option B:** **Polymerase Chain Reaction (PCR)** is a laboratory technique used to amplify specific DNA sequences. PCR is often used in conjunction with other techniques, such as sequencing or hybridization, to analyze DNA. However, it is not a direct method for differentiating chromosomes.
**Option C:** **Chromosomal Microarray Analysis (CMA)** is a technique used to detect copy number variations in the genome. CMA can identify chromosomal deletions or amplifications, but it is not the primary method used to differentiate the chromosomes of normal and cancer cells.
**Option D:** **Flow Cytometry** is a technique used to analyze the physical and chemical characteristics of cells in a fluid. Flow cytometry is often used to analyze the expression of specific proteins or other cellular markers, but it is not a direct method for differentiating chromosomes.
**Clinical Pearl / High-Yield Fact**
When differentiating between normal and cancer cells, it is essential to consider the specific chromosomal abnormalities associated with each type of cancer. For example, the presence of the Philadelphia chromosome in a patient's bone marrow cells can be diagnostic of chronic myeloid leukemia.
**Correct Answer:** C.