Gene for retinoblastoma is located on –
**Core Concept**
The question is testing your knowledge of the genetics underlying retinoblastoma, a rare form of eye cancer that affects children. Retinoblastoma is a tumor suppressor gene that plays a crucial role in regulating cell growth and division.
**Why the Correct Answer is Right**
The retinoblastoma gene (RB1) is a tumor suppressor gene that is located on the long arm of chromosome 13 (13q14). It encodes for a protein that regulates the cell cycle, specifically inhibiting the transition from the G1 phase to the S phase. When the RB1 gene is mutated or deleted, it can lead to uncontrolled cell growth and tumor formation. The RB1 gene is a classic example of a tumor suppressor gene, which means it acts to prevent cancer by regulating cell growth and division.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not correct because it does not specify the correct chromosome or location of the retinoblastoma gene.
**Option B:** This option is not correct because it is a different gene, associated with a different type of cancer.
**Option C:** This option is not correct because it is a different gene, associated with a different type of cancer.
**Clinical Pearl / High-Yield Fact**
Retinoblastoma is a classic example of a hereditary cancer syndrome, where a single mutation in a tumor suppressor gene can lead to a high risk of developing cancer. This highlights the importance of genetic counseling and testing for families with a history of cancer.
**Correct Answer:** D.