“Mutations that become so common that they affect more than 1% of a population are called polymorphisms (for example, the human blood types A, B, AB, and O).“
The claim that human blood types are mutations should be supported with experimental evidence of biologically-based cause and effect. Ask your professor, “What evolutionary event linked the mutation to natural selection and the evolution of human blood types?
How did nutrient-dependent cell type differentiation become mutation-initiated cell type differentiation, when it is nutrient-dependent, receptor-mediated in human blood cells, and pheromone-controlled by RNA-mediated events in species from microbes to all other primates?”
Tell your professor to stop touting the pseudoscientific nonsense of evolutionary theory and learn about RNA-mediated events that link nutrient uptake to cell type differentiation, which is controlled by feedback loops. The feedback loops link food odors and pheromones to reproduction in species from microbes to man, according to at least one Nobel Laureate and her co-authors.
The basics of cell type nutrient-dependent pheromone-controlled cell type differentiation are detailed in less than 2 minutes in this video.
Additional complexity is included in this 5.5 minute video from my last presentation. Examples of ecological speciation from nematodes to primates may help others who are Combating Evolution to Fight Disease.