Motoo Kimura

Definition

Motoo Kimura was a Japanese evolutionary biologist known for his contributions to the neutral theory of molecular evolution. This theory posits that most evolutionary changes at the molecular level are caused by random genetic drift of mutant alleles that are neutral in terms of their effects on fitness, rather than being driven primarily by natural selection. Kimura's work has had a significant impact on our understanding of genetic variation and molecular evolution.

5 Must Know Facts For Your Next Test

1. Motoo Kimura introduced the neutral theory in his 1968 paper, emphasizing the role of random processes in molecular evolution.
2. Kimura's work provided a framework for understanding the patterns of genetic diversity observed in natural populations.
3. The neutral theory challenged the dominance of natural selection as the primary driver of molecular evolution and opened up new avenues for research.
4. Kimura also contributed to the development of methods for analyzing molecular data, including statistical techniques to estimate mutation rates.
5. His ideas have influenced various fields, including population genetics, conservation biology, and phylogenetics.

Review Questions

• How does Motoo Kimura's neutral theory challenge traditional views on natural selection?
  • Motoo Kimura's neutral theory challenges traditional views by suggesting that many genetic variations do not significantly affect an organism's fitness and are instead subject to random genetic drift. While natural selection focuses on advantageous traits improving survival and reproduction, Kimura posited that most mutations are neutral and accumulate over time without any adaptive significance. This perspective shifts the emphasis from a purely selection-driven model to one that incorporates randomness in evolutionary processes.
• In what ways did Motoo Kimura's contributions to molecular evolution impact our understanding of genetic diversity in populations?
  • Motoo Kimura's contributions emphasized that much of the genetic diversity seen within populations can arise from neutral mutations rather than solely from adaptive changes driven by natural selection. This realization prompted researchers to reevaluate the mechanisms behind genetic variation, leading to a broader understanding of how evolutionary processes shape genomes. By framing genetic drift as a significant force, Kimura's work has helped elucidate patterns of molecular evolution across various species.
• Evaluate the implications of Motoo Kimura's neutral theory for contemporary research in evolutionary biology.
  • The implications of Motoo Kimura's neutral theory for contemporary research are profound, as it reshapes how scientists approach questions about genetic variation and evolution. By acknowledging the role of random processes alongside natural selection, researchers can better interpret genetic data and develop models that accurately reflect evolutionary dynamics. This approach has been instrumental in fields such as conservation biology, where understanding genetic diversity is critical for species preservation efforts, and phylogenetics, where it aids in reconstructing evolutionary histories. As a result, Kimura's insights continue to influence ongoing research and debates within evolutionary biology.

Related terms

Neutral Theory: A theory that suggests that much of the genetic variation in populations is due to random genetic drift of alleles that are selectively neutral.

Genetic Drift: A mechanism of evolution that refers to random changes in allele frequencies in a population, which can lead to significant evolutionary changes over time.

Molecular Evolution: The study of evolutionary changes at the molecular level, particularly focusing on changes in genes and proteins over time.