We Learned in Chapter 5 That the Benefit of Having

Essay

We learned in Chapter 5 that the benefit of having and expressing multiple MHC class I and class II genes is that it increases the number and variety of pathogen-derived peptide antigens that can potentially be presented to T cells.If more is better,then why has natural selection not favored the evolution of more than three genes each for MHC class I and MHC class II?