What is genetic drift?

Genetic drift is defined as a mechanism of evolution that leads to random changes in allele frequencies within a population over time. This phenomenon occurs primarily in small populations where random events can have a more significant impact on the genetic makeup of the population compared to larger populations. In small groups, certain alleles may become more or less common simply due to chance fluctuations in reproduction or survival, rather than direct selection for those traits.

For example, if a few individuals with a unique allele reproduce more successfully than others for random reasons (such as a natural disaster that inadvertently affects other individuals), the allele frequency can shift significantly over generations, even if that allele does not confer any survival advantage. This randomness distinguishes genetic drift from other evolutionary mechanisms like natural selection, where the changes in allele frequency are driven by the advantages or disadvantages those traits provide in a given environment.

In contrast to genetic drift, intentional alterations of genetic material by humans are described by practices such as genetic engineering or selective breeding, which involve deliberate manipulation rather than random change. Systematic selection by natural forces refers to natural selection, where advantageous traits are selectively favored. Lastly, cloning is a laboratory technique for producing identical copies of organisms, which does not involve changes in allele frequencies resulting from natural processes.