Question

Consider a population in which heterozygotes at a certain locus (gene) have much larger bodies than homozygotes of either allele. This large body size results in a selective advantage. What type of selection is this: disruptive, stabilizing, or directional? Explain your answer.

Answer 1

Directional selection - In this type of natural selection an extreme phenotype such as the larger body size is favored over the smaller body size, causing the allele frequency to shift over time in the direction of this phenotype. If a population follows a stabilizing selection, the phenotype from the mid range will be favored and in the case of diruptive selection, extreme values for a trait (both largest and smallest) are favored over intermediate values. Two distinct population will result from a disruptive selection.