What is the chromosomal aberration seen when there is transverse division in centromere:
## **Core Concept**
The question pertains to the type of chromosomal aberration that occurs due to a transverse division in the centromere. Chromosomal aberrations are changes in the structure or number of chromosomes and can result from various errors during cell division. The centromere is a critical region of a chromosome that links sister chromatids and is essential for the proper segregation of chromosomes during mitosis and meiosis.
## **Why the Correct Answer is Right**
When there is a transverse division in the centromere, it leads to a specific type of chromosomal abnormality. Normally, the centromere divides longitudinally, allowing sister chromatids to separate properly. However, if the centromere divides transversely, it results in one chromatid receiving the centromere and the other not. This situation leads to the formation of **isochromosomes**. Isochromosomes are chromosomes that have lost one set of chromatids and have gained a duplicate set from the other chromatid, essentially having two identical copies of one arm and no copy of the other arm.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately describe the chromosomal aberration resulting from transverse centromeric division.
- **Option B:** This option might describe another type of chromosomal aberration but does not accurately represent the outcome of transverse division in the centromere.
- **Option D:** Similarly, this option does not correctly describe the formation of isochromosomes or the consequence of transverse centromeric division.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that isochromosomes can lead to various genetic disorders, depending on which chromosome is involved and which arm is duplicated. For instance, **isochromosome Xq** (i(Xq)) is associated with Turner syndrome, a condition that affects females, causing short stature and ovarian failure, among other features.
## **Correct Answer:** . Isochromosome.