Question

The number of major histocompatibility (MHC) protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because ________.

Answer 1

Answer:

The correct answer is "each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene".

Explanation:

In normal conditions, an individual has only two different alleles for a given gene: one inherited from his mother and the other from his father. However, this does not mean that among humans, there are only two different alleles for each gene. The major histocompatibility (MHC) genes are a clear example of this, since there are multiple combinations for each MHC class. For instance, there are 40 very similar alleles only for the HLA-B27 subtype.