Final answer:
Most genes in populations have more than two forms, or multiple alleles, contributing to genetic diversity, though individuals carry only two alleles for any given gene.
Step-by-step explanation:
Yes, most genes in populations exist in more than two forms, a phenomenon known as multiple alleles, even though each individual carries, at most, two different alleles for a particular gene. While Mendel's studies suggested the existence of only two alleles (one dominant and one recessive), this is an oversimplification. At the population level, there can be many different alleles for a single gene, increasing genetic diversity.
For instance, the ABO blood type system in humans is determined by three alleles (IA, IB, and i). While any single individual can only have two of these alleles, the population as a whole maintains all three alleles across different individuals. This scenario applies not just to blood types but to many genetic traits, where the combination of multiple alleles leads to the rich genetic variation observed within a population. The term wild type denotes the most common phenotype or genotype in a population, with all other forms being considered variants.