BRCA-1 and BRCA-2 located respectively on?
**Core Concept**
The BRCA-1 and BRCA-2 genes are tumor suppressor genes that play a crucial role in maintaining genomic stability by participating in the repair of DNA double-strand breaks. These genes are located on different chromosomes and are associated with an increased risk of breast, ovarian, and other cancers when mutated.
**Why the Correct Answer is Right**
The BRCA-1 gene is located on chromosome 17q21, while the BRCA-2 gene is located on chromosome 13q12.3. These genes encode proteins that are involved in the repair of DNA double-strand breaks through homologous recombination. When these genes are mutated, the repair process is disrupted, leading to genomic instability and an increased risk of cancer. The BRCA-1 protein is involved in the repair of double-strand breaks through the formation of a complex with other proteins, including RAD51 and BRCA-2. The BRCA-2 protein, on the other hand, is involved in the loading of RAD51 onto the DNA, facilitating the repair of double-strand breaks.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct chromosome locations of the BRCA-1 and BRCA-2 genes.
* **Option B:** This option is incorrect because it does not accurately describe the locations of the BRCA-1 and BRCA-2 genes.
* **Option D:** This option is incorrect because it does not provide the correct chromosome locations of the BRCA-1 and BRCA-2 genes.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that mutations in the BRCA-1 and BRCA-2 genes are associated with an increased risk of breast and ovarian cancers, and individuals with these mutations may benefit from enhanced surveillance and preventive measures, such as mastectomy or salpingo-oophorectomy.
**Correct Answer: C. 17q21 and 13q12.3**