Question

Which of the following genes responsible for graft rejection in humans?

• A. Highly polymorphic HLA genes
• B. APP genes
• C. hMSH₂ gene
• D. FMR₁ gene

Answer 1

The Correct Option is A

The question asks which genes are responsible for graft rejection in humans. The correct answer is "Highly polymorphic HLA genes." Let's break down the reasoning:

1. Understanding Graft Rejection: Graft rejection is the immune response against a transplanted organ or tissue. The immune system recognizes the transplanted organ as foreign due to differences in certain proteins between the donor and recipient.
2. Role of HLA Genes:
   • The Human Leukocyte Antigen (HLA) system is a group of genes in humans that encode for proteins on the surface of cells that are responsible for regulation of the immune system.
   • HLA genes are highly polymorphic, meaning there is a lot of genetic variation in the population, which causes the immune system to recognize the graft as foreign, leading to rejection.
3. Eliminating Other Options:
   • APP genes: These are associated with amyloid precursor protein, involved in Alzheimer’s disease, not with graft rejection.
   • hMSH₂ gene: This gene is related to repairing DNA mismatch, typically discussed in the context of certain cancers, not graft rejection.
   • FMR₁ gene: This gene is associated with fragile X syndrome, a genetic condition leading to intellectual disability, and is unrelated to graft rejection.
4. Conclusion: The correct option “Highly polymorphic HLA genes” is responsible for graft rejection due to their role in the immune system and genetic variability.

Hint: When dealing with questions related to graft rejection, always consider the role of HLA genes, as they are crucial in distinguishing self from non-self in the immune system.