Q1. The frequency of PTC nontasters (tt genotype) is advanced than expected if there is a selective advantage to tasting bitter plants or foods in general. PTC is similar to known toxic alkalods that can lead to problems in thyroid metabolism, thus losing the ability to taste these compounds should be a disadvantage. There is evidence that an evolutionary process known as ”balancing selection” might be responsible, tending to favor heterozygotes (more fit) over either the strong tasters (TT) or non-tasters (tt). What advantage will heterozygotes have over the homozygotes?

Q2. Why selection inevitably favors any gene that is good at getting into the next generation, regardless of whether that gene helps or hurts the ecosystem, the species, the group, or even the individual?