Epigenetics and the Evolution of Darwin's Finches - Review


The article "Epigenetics and the Evolution of Darwin's Finches" by Michael K. Skinner challenges neo-Darwinism by proposing that epigenetic changes, in addition to genetic mutations, can play a significant role in evolution. Neo-Darwinism is the prevailing theory of evolution, which holds that evolution is driven by natural selection acting on genetic mutations. Skinner argues that epigenetic changes can accumulate over generations to produce new species without natural selection on mutations.

Skinner supports his argument with evidence from studies of Darwin's finches. Darwin's finches are a group of closely related birds that live on the Galapagos Islands. The finches have evolved into a wide variety of species, each with a different beak shape that is adapted to a particular food source. Skinner's studies have shown that the epigenetic changes that control beak shape can be inherited from parents to offspring. This suggests that epigenetic changes can cause rapid adaptation without mutations and that they can play a role in the evolution of new species.

Skinner's work has important implications for our understanding of evolution. It suggests that evolution is not just a matter of random genetic mutations, but that it can also be influenced by environmental factors that can cause epigenetic changes. This means that evolution can be more rapid and adaptive than previously thought.

Skinner's work is still in its early stages, and more research is needed to fully understand the role of epigenetics in evolution. However, his findings suggest that epigenetics is a major player in the evolutionary process, and that it challenges the traditional view of evolution as being driven solely by genetic mutations.

In addition to the studies of Darwin's finches, there is other evidence that supports the role of epigenetics in evolution. For example, studies have shown that epigenetic changes can be induced by environmental factors such as diet, stress, and pollution. These changes can then be inherited by offspring, and they can have a significant impact on the organism's phenotype (physical appearance and behavior).

The evidence suggests that epigenetic changes can play a significant role in evolution, both in the short term and over long periods of time. This challenges the traditional view of evolution as being driven solely by genetic mutations. However, it is important to note that epigenetic changes are not the only factor that drives evolution.

The study of epigenetics is a rapidly growing field, and it is likely to shed new light on the mechanisms of evolution in the years to come. By understanding the role of epigenetics in evolution, we can better understand how life on Earth has changed over time, and how it may continue to change in the future.

Here are some specific examples of how epigenetic changes have been shown to affect evolution:

  • In one study, mice that were exposed to high levels of stress during pregnancy had offspring with smaller brains and poorer cognitive abilities. These epigenetic changes were inherited by the offspring, and they persisted even when the offspring were raised in a stress-free environment.

  • In another study, rats that were exposed to a pesticide called dioxin had offspring with increased susceptibility to cancer. These epigenetic changes were also inherited by the offspring, and they persisted for at least two generations.

  • Studies of plants have shown that epigenetic changes can affect a wide variety of traits, including flowering time, drought tolerance, and resistance to pests.

These are just a few examples of the many ways that epigenetic changes can affect evolution. As our understanding of epigenetics continues to grow, we are likely to learn even more about its role in the evolutionary process.

Article Snippets

The prevailing theory for the molecular basis of evolution involves genetic mutations that ultimately generate the heritable phenotypic variation on which natural selection acts.

However, epigenetic transgenerational inheritance of phenotypic variation plays an important role in evolutionary change.

This study was designed to compare epigenetic changes among several closely related species of Darwin’s finches, a well-known example of adaptive radiation.

genetic mutations using copy number variation (CNV) were compared with epigenetic alterations associated with differential DNA methylation regions (epimutations)

Epimutations were more common than genetic CNV mutations among the five species; furthermore, the number of epimutations increased monotonically with phylogenetic distance

Interestingly, the number of genetic CNV mutations did not consistently increase with phylogenetic distance {eg mutations did not vary with differing phenotypes}

Specific epimutations were associated with genes related to the bone morphogenic protein, toll receptor, and melanogenesis signaling pathways.

Species-specific epimutations were significantly overrepresented in these pathways.

epigenetic changes contribute to the molecular basis of the evolution of Darwin’s finches.

In order for inherited epigenetic changes to play a significant role in microevolution, they must persist for tens of generations, or longer

It is conceivable that epigenetic changes may also accumulate over longer periods of evolutionary time, contributing to processes such as adaptive radiation

This hypothesis assumes that epigenetic changes persist over thousands of generations.

Only selection on phenotypic traits with a heritable basis can lead to evolutionary change

As epigenetic changes are also influenced by environmental factors, and can be heritable across generations, they provide another molecular mechanism that can influence evolutionary change.

Although Lamarck (1802) proposed that environmental factors can influence inheritance directly, his mechanism has not been widely recognized as a component of modern evolutionary theory.

epigenetic changes can, in fact, increase the heritable phenotypic variation.

epigenetics appears to provide a molecular mechanism that can increase phenotypic variation.

Studies such as these suggest that environmental epigenetics plays a major role in evolutionary changes through processes, such as sexual selection.

Recent reviews suggest a pervasive role for epigenetics in evolution

This study provides one of the first genome-wide comparisons of genetic and epigenetic mutations among related species of organisms

There were relatively more epimutations than genetic CNV mutations among the five species of Darwin’s finches, which suggests that epimutations are a major component of genome variation during evolutionary change

In contrast, there was no significant relationship between the number of genetic CNV changes and phylogenetic distance. {eg epimutations not mutations accounts for phenotypic changes more completely}.

Among the five species of finches there were fewer genetic mutations (CNV) than epigenetic mutations.

the number of epimutations increased monotonically with phylogenetic distance.

Genetic mutations are postulated to provide much of the variation upon which natural selection acts.

However, genetic changes alone are limited in their ability to explain phenomena ranging from the molecular basis of disease etiology to aspects of evolution.

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