What is a defining characteristic of genetic drift?

Genetic drift is a phenomenon that results from random sampling effects within a population's gene pool. This randomness means that certain alleles may be passed on to the next generation purely by chance rather than by selecting for advantageous traits. For instance, in a small population, if a few individuals carry a specific allele and happen to reproduce more frequently than others, that allele could become more prevalent in subsequent generations s without any adaptive advantage. This randomness can lead to significant changes in allele frequencies over time, especially in small populations, highlighting its defining characteristic as a non-selective process that operates independently of environmental pressures or deliberate breeding methods.

While genetic drift can result in the loss of genetic diversity, this is a consequence of the random fluctuations rather than a defining characteristic. Similarly, it is distinct from controlled breeding, which involves intentional selection, and is not directly influenced by environmental factors in the way that selection is. Thus, the aspect of randomness is what quintessentially distinguishes genetic drift from other evolutionary mechanisms.