What genetic variation can result from external environmental factors?

Genetic variation arising from external environmental factors is primarily illustrated through gene mutation. Mutations can occur when DNA is exposed to certain environmental influences, such as radiation, chemicals, and infectious agents. These external factors can cause changes in the nucleotide sequence of genes, leading to new alleles and, consequently, variability within a population.

Mutations can be spontaneous or induced by environmental stresses, and they can have various effects on the organism, ranging from neutral to beneficial or harmful. For instance, UV radiation can cause thymine dimers in DNA, which, if not repaired, can lead to changes in the genetic code, resulting in mutations. This process is a fundamental example of how environmental factors can drive genetic diversity, allowing for adaptation and evolution over generations.

Options like gene editing involve intentional alterations performed in a laboratory setting and do not occur naturally as a direct result of environmental factors. Genome alteration is a broader term that might suggest changes to the overall structure of an organism's genome, which isn't solely the result of external factors. Genetic profiling is a technique used for analyzing an individual's genetic information but does not itself represent a source of genetic variation.