Neutral theory of molecular evolution

The Neutral Theory of Molecular Evolution, proposed by Motoo Kimura in the 1960s, suggests that most genetic changes in organisms are not driven by natural selection but occur randomly through mutations that do not significantly affect survival or reproduction. According to this theory, many variations at the molecular level, such as in DNA sequences, are “neutral,” meaning they neither benefit nor harm the organism. Over time, these neutral mutations can accumulate and lead to diversity within and between species, emphasizing that some evolutionary changes result from chance rather than adaptive advantages.