Kary otyping is done in which phase of cell cycle-
**Core Concept**
Karyotyping is a process of arranging the chromosomes in a specific order to identify genetic abnormalities. It involves the preparation of chromosomes from a cell sample, which are then analyzed under a microscope. The chromosomes must be in a specific phase of the cell cycle to be accurately analyzed.
**Why the Correct Answer is Right**
During Metaphase, the chromosomes align at the center of the cell, attached to the spindle fibers. This alignment is crucial for karyotyping as it allows the chromosomes to be visualized and analyzed in a linear fashion. The chromosomes are condensed and have distinct banding patterns, making it easier to identify specific chromosomes and any genetic abnormalities. The alignment of chromosomes in Metaphase also enables the identification of any chromosomal translocations, deletions, or duplications.
**Why Each Wrong Option is Incorrect**
**Option A:** Anaphase is the phase where the sister chromatids separate and move to opposite poles of the cell, making it difficult to accurately analyze the chromosomes.
**Option C:** Telophase is the phase where the nuclear envelope reforms, and the chromosomes begin to decondense, making it challenging to visualize the chromosomes.
**Option D:** S phase is the phase of DNA replication, where the chromosomes are not yet condensed and are difficult to analyze.
**Clinical Pearl / High-Yield Fact**
In addition to karyotyping, other techniques such as Fluorescence In Situ Hybridization (FISH) and Polymerase Chain Reaction (PCR) can be used to analyze genetic material. These techniques are often used in conjunction with karyotyping to confirm genetic abnormalities.
**✓ Correct Answer: B. Metaphase**