Which type of variation arises from changes in DNA that do not affect reproductive success?

Neutral variation refers to genetic changes that occur in an organism's DNA but do not have a significant impact on its fitness or reproductive success. This type of variation is often the result of mutations that do not alter the function of genes or lead to changes in traits that would influence selection pressures. As such, these variations can persist in a population over time without affecting survival or reproduction, allowing them to accumulate through evolutionary processes like genetic drift.

In contrast, adaptive variation involves changes that improve an organism's ability to survive and reproduce in a particular environment, making it subject to natural selection. Genetic variation is a broader term that encompasses all types of variations in the genetic makeup of individuals within a population, including both neutral and adaptive variations. Phenotypic variation refers to observable traits of an organism, which can be influenced by both genetic and environmental factors, but does not specifically address the genetic basis of variation. Thus, the distinction of neutral variation is key in understanding genetic diversity that does not directly relate to reproductive fitness.