Mutational bias causes rapid adaptation without neo-Darwinism


The article "The Role of Mutation Bias in Adaptive Evolution" by Storz et al. (2019) examines the extent to which mutational bias in the production of genetic variation influences outcomes and pathways of adaptive molecular evolution.

Mutation bias is the non-random distribution of mutations across the genome. In some cases, certain types of mutations are more likely to occur than others. For example, in the genomes of at least some vertebrate taxa, an important form of mutation bias involves changes at CpG dinucleotides. A CpG dinucleotide is a sequence of DNA that consists of a cytosine nucleotide followed immediately by a guanine nucleotide. Mutations at CpG dinucleotides occur at an elevated rate relative to mutations at other dinucleotides.

The authors of the article argue that mutation bias can influence the outcomes of adaptive evolution in several ways. First, mutation bias can create genetic variation that is favorable for adaptation. If certain types of mutations are more likely to occur than others, then the pool of genetic variation will be biased towards those types of mutations. This can make it more likely that adaptive mutations will arise.

Second, mutation bias can influence the direction of adaptive evolution. This can lead to adaptive changes in a particular direction, even if there are other possible adaptive changes that could occur.

The authors of the article provide several examples of how mutation bias can influence adaptive evolution. One example is the evolution of hemoglobin (Hb) in high-altitude birds. Hb is a protein that transports oxygen in the blood. In high-altitude environments, the air is thinner, so there is less oxygen available. Birds that live in high-altitude environments have evolved Hb proteins with higher oxygen affinity, which allows them to extract more oxygen from the air.

The authors of the article found that the mutations that are responsible for the increased oxygen affinity of Hb in high-altitude birds are enriched for CpG mutations. This suggests that mutation bias has played a role in the evolution of Hb in these birds.

The authors of the article conclude that mutation bias is an important factor to consider in understanding adaptive evolution. Mutation bias can create genetic variation that is favorable for adaptation, and it can also influence the direction of adaptive evolution. The article by Storz et al. (2019) provides a valuable contribution to our understanding of the role of mutation bias in adaptive evolution. The authors provide evidence that mutation bias can influence the outcomes and pathways of adaptive evolution, and they discuss the implications of this finding for our understanding of evolution. The article is well-written and well-argued, and it provides a valuable resource for anyone interested in the topic of adaptive evolution.

In addition to the article by Storz et al. (2019), there are a number of other studies that have investigated the role of mutation bias in adaptive evolution. For example, a study by Stoltzfus and McCandlish (2018) found that mutation bias can influence the rate of adaptive evolution. The authors of this study found that mutation bias can increase the rate of adaptive evolution in small populations, but it can decrease the rate of adaptive evolution in large populations.

Another study by Eyre-Walker et al. (2017) found that mutation bias can influence the distribution of adaptive mutations across the genome. The authors of this study found that adaptive mutations are more likely to occur at sites that are already under selection. This suggests that mutation bias can help to amplify the effects of natural selection.

The research on the role of mutation bias in adaptive evolution is still in its early stages, but it is clear that mutation bias is an important factor to consider in understanding how evolution works. Mutation bias can influence the outcomes and pathways of adaptive evolution, and it can also interact with natural selection to produce complex patterns of evolution.

Mutation bias works outside of neo-Darwinism. Neo-Darwinism is a theory of evolution that states that evolution is driven by two main processes: random (not biased), mutations and natural selection. Random mutations are the process by which new genetic variation is introduced into a population, and natural selection is the process by which those genetic variants that are most beneficial to the organism's survival and reproduction are passed on to the next generation.

Mutation bias is the phenomenon whereby some types of mutations are more likely to occur than others. This can happen for a variety of reasons, such as the chemical structure of DNA, the environment, or the organism's own genes. It's a cellular design mechanism which filters environmental contributions. Mutation bias can have a significant impact on evolution, as it can lead to the accumulation of beneficial mutations in a population.

Mutation bias works outside of neo-Darwinism. For example, in some cases, mutation bias can be driven by non-Darwinian forces, such as genetic drift. Genetic drift is the random change in allele frequencies in a population over time. If mutation bias causes certain types of mutations to be more likely to occur, then genetic drift can amplify this effect and lead to the fixation of those mutations in the population.

Mutation bias plays a role in other evolutionary processes, such as adaptation and speciation. For example, mutation bias can help to explain why some species are more adaptable to change than others. In species with high mutation rates, there is a greater chance that beneficial mutations will occur, which can help the species to adapt to new environments.

Mutation bias is a complex phenomenon with a wide range of implications for evolution. It plays a significant role in shaping the course of evolution, outside of neo-Darwinism.


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