In the context of evolution, certain traits or alleles of genes segregating within a population may be subject to selection. Under selection, individuals with advantageous or "adaptive" traits tend to be more successful than their peers reproductively—meaning they contribute more offspring to the succeeding generation than others do. When these traits have a genetic basis, selection can increase the prevalence of those traits, because offspring will inherit those traits from their parents. When selection is intense and persistent, adaptive traits become universal to the population or species, which may then be said to have evolved. Scientists who do experimental genetics employ artificial selection experiments that permit the survival of organisms with user-defined phenotypes. Artificial selection is widely used in the field of microbial genetics, especially molecular cloning.