Epigenetics drives Neo-Darwinian Genetic Drift


The journal article "The adaptive value of epigenetic mutation: Limited in large but high in small peripheral populations" delves into the significant role of epigenetic mutations in shaping adaptation, particularly within the context of peripheral populations. Its findings present a perspective that challenges traditional neo-Darwinian views, especially regarding the influence of genetic drift.

Here's a breakdown of the key points and how they relate to the challenge of neo-Darwinian genetic drift:

Core Findings:

  • Epigenetic Mutation Rate: The study highlights the significantly higher rate of epigenetic mutations compared to genetic mutations. This rapid turnover offers a more immediate source of phenotypic variation.

  • Peripheral Population Dynamics: It distinguishes between large and small peripheral populations, demonstrating that the impact of epimutations varies considerably between them.

  • Large Peripheral Populations: In these populations, where genetic drift is minimal, the study suggests that epimutations with random fitness effects primarily aid adaptation when migration rates are high, essentially overriding divergent selection.

  • Small Peripheral Populations: Here, where genetic drift is a powerful force, epimutations contribute to adaptation under a broader spectrum of evolutionary scenarios.

Challenging Neo-Darwinian Genetic Drift:

Neo-Darwinism, in its classical form, emphasizes the central role of genetic mutations and natural selection in evolution. Genetic drift, the random fluctuation of allele frequencies, is acknowledged, but its influence is often considered more pronounced in small populations, where its effects can override selection.

The study's findings challenge this view in several ways:

  • Epigenetics as a Significant Evolutionary Force: The study elevates epigenetics from a peripheral phenomenon to a significant driver of adaptive change. This challenges the strict gene-centric view of neo-Darwinism. Epigenetic changes, which alter gene expression without changing the underlying DNA sequence, provide a rapid and flexible mechanism for adaptation.

  • Epigenetics and Drift Interaction: The study demonstrates a complex interaction between epigenetic mutations and genetic drift. In small populations, where drift is strong, epimutations can enhance adaptation under a wider range of conditions. This suggests that epigenetic variation can counteract the potentially maladaptive effects of drift.

  • Adaptive Potential of Random Epimutations: The finding that even random epimutations can enhance adaptation, particularly when coupled with high migration, suggests that the evolutionary process may be more flexible and less strictly deterministic than traditional neo-Darwinian models imply. It shows that even random changes can be useful.

  • Speed of Adaptation: Epigenetic changes can happen faster than genetic changes. This speed allows for quicker adaptation to changing environments. This quick adaptation is very important for small populations that are highly vulnerable to environmental change.

In essence, the study suggests that:

  • Evolutionary adaptation is not solely driven by genetic mutations and selection.

  • Epigenetic variation offers a significant and rapid source of adaptive potential.

  • The interplay between epigenetics and genetic drift is more complex than previously thought, particularly in small populations.

By illuminating the adaptive value of epigenetic mutations, this research contributes to a more comprehensive understanding of evolutionary processes, pushing beyond the limitations of purely gene-centric neo-Darwinian perspectives.


Comments

Post a Comment

Popular posts from this blog

No, the EES is not just a add on to Neo-Darwinism aka the Modern Synthesis

Image
" The summary of the state of affairs on the 150th anniversary of the Origin is somewhat shocking: in the post-genomic era, all major tenets of the Modern Synthesis fthe theory of evolution) are, if not outright overturned replaced by a new and incomparably more complex vision of the key aspects of evolution (EES). So, not to mince words , the Modern Synthesis is gone" -Eugene Koonin, an evolutionary biologist (Cited by over 270,000 evolutionary scientists.) The Extended Evolutionary Synthesis (EES) represents a significant departure from the traditional neo-Darwinian framework, also known as the Modern Synthesis . While both theories aim to explain evolutionary change, they differ fundamentally in their underlying mechanisms and the roles they assign to various biological processes. A crucial point of divergence lies in the interpretation and application of the term " evolutionary ," particularly concerning the incorporation of epigenetic mechanisms....
Read more

Is the random mutational model of evolution on its way out?

Image
While the random mutational model of evolution has long been a cornerstone of evolutionary biology, the Extended Evolutionary Synthesis (EES) and the study of epigenetics are challenging its core assumptions. The Random Mutational Model and Its Limitations The traditional view of evolution, often called the Modern Synthesis or neo-Darwinism , emphasizes random genetic mutations as the primary source of variation. Natural selection then acts upon this variation, favoring individuals with advantageous traits. This model has been successful in explaining some evolutionary phenomena, but it also has limitations: It struggles to explain complex adaptations: The idea that complex features like the eye or the immune system arose solely through random mutations seems statistically improbable. It overlooks the role of the environment: The traditional model treats the environment as a selective force, but it doesn't fully consider how organisms can actively respond to and s...
Read more

Natural Selection has not been accurately measured since Darwin

Image
Francis Crick's term "frozen accident" falsely described the seeming rigidity of the genetic code, its apparent inability to accommodate additional amino acids beyond the standard 20. This observation had puzzled scientists for decades, as the genetic code seems to have reached a plateau in its expansion despite the potential for incorporating new amino acids with novel properties. NeoDarwinian thinking reasoned greater natural selection could occur with more codons. Several hypotheses were put forward to explain this apparent standstill in the genetic code's evolution. Crick and others  eventually applied natural selection to think redundant codons were neutral as to account for neutral selection . The question of why the genetic code stopped incorporating new amino acids remained a fascinating topic in evolutionary biology till Cas9 Crispr. The redundancy of codons, where multiple codons can specify the same amino acid, has long been considered a neutr...
Read more