DNA And Gene Expression Practice Test

Genetic load describes the decrease in a population’s average fitness caused by the buildup of deleterious mutations over generations. Mutations continually arise, and while natural selection removes many harmful changes, some persist—especially if they’re recessive or kept in check by drift in small populations. Over time, this accumulation lowers the overall vitality or reproductive success of the species, which is what the term genetic load captures. Epigenetics refers to heritable changes in gene expression that don’t alter the DNA sequence, so it’s not about accumulating mutations. Activators are proteins that boost transcription, not a concept about mutation buildup. Hox genes are developmental regulators that shape body plans, again unrelated to the accumulation of mutations over time.