Recombination and GC-biased Gene Conversion challenges NeoDarwinism

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The article "Influence of Recombination and GC-biased Gene Conversion on the Adaptive and Nonadaptive Substitution Rate in Mammals versus Bird" by Bolívar et al. (2016) investigates how recombination and GC-biased gene conversion (gBGC) affect coding sequence evolution in mammals and birds.

Recombination is a process that exchanges genetic material between homologous chromosomes during meiosis. gBGC is a type of gene conversion that disproportionately favors the conversion of A and T nucleotides to G and C nucleotides. Both recombination and gBGC are thought to play a role in shaping the evolution of genes, but their effects are still being studied.

Bolívar et al. analyzed proteome-wide data from six species of mammals (catarrhine primates) and six species of birds (Galloanserae).  Their results showed that recombination and gBGC both have a decreasing effect on the dN/dS ratio in both mammals and birds. This suggests that both processes help to remove deleterious mutations from the population. However, the authors also found that recombination has a mutagenic effect that is independent of gBGC. This means that recombination can actually create new mutations, even though it also helps to remove them.

The authors also found some differences between mammals and birds in the effects of recombination and gBGC. For example, they found that the mutagenic effect of recombination is stronger in birds than in mammals. They also found that gBGC has a stronger effect on AT → GC mutations in mammals than in birds.

Overall, the study by Bolívar et al. provides new insights into the complex interplay between recombination, gBGC, and the evolution of coding sequences in mammals and birds. Their findings suggest that both processes play an important role in shaping the genetic diversity of these two groups of animals.

Here are some of the key implications of this study:

  • Recombination and gBGC both help to remove deleterious mutations from the population, but they also have some mutagenic effects.

  • The mutagenic effect of recombination is stronger in birds than in mammals.

  • gBGC has a stronger effect on AT → GC mutations in mammals than in birds.

  • The findings of this study suggest that recombination and gBGC play an important role in shaping the genetic diversity of mammals and birds.

This study has important implications for our understanding of the evolution of genes and genomes. It also has potential implications for the development of new medical treatments and therapies.

Neodarwinism is a theory of evolution that combines Charles Darwin's theory of natural selection with the principles of modern genetics.

One of the key tenets of neodarwinism is that evolution is driven by natural selection, which is the differential survival and reproduction of individuals with favorable traits. Natural selection can only act on heritable variation, which is variation that is passed down from parents to offspring.

Recombination and GC-biased gene conversion (gBGC) are both molecular processes that can generate heritable variation. Recombination is the process by which genetic material is exchanged between homologous chromosomes during meiosis. gBGC is a type of gene conversion that favors the conversion of A and T nucleotides to G and C nucleotides.

Both recombination and gBGC can challenge neodarwinism by generating new genetic variation that is not the result of natural selection. 

In addition, recombination can break down linkage between genes, which can also challenge neo darwinism. Linkage is the physical association of genes on chromosomes. When genes are linked, they are more likely to be inherited together. This can lead to the coevolution of genes, even if they are not under the same selective pressure. Recombination can break down linkage and allow genes to evolve independently, which can lead to new and unexpected evolutionary outcomes.

The article provides evidence that recombination and gBGC have a significant impact on the rate of coding sequence evolution in mammals and birds.

This finding suggests that recombination and gBGC play an important role in removing deleterious mutations from the population. However, the authors also found that recombination has a mutagenic effect that is independent of gBGC. This means that recombination can actually create new mutations, even though it also helps to remove them.

The findings of this study suggest that recombination and gBGC play a more complex role in evolution than previously thought. They also suggest that neodarwinism may need to be modified to account for the effects of these processes.

Here are some specific ways in which the article challenges neodarwinism:

  • It shows that recombination and gBGC can generate new genetic variation that is not the result of natural selection.

  • It shows that recombination can break down linkage between genes, which can allow genes to evolve independently of each other.

  • It shows that recombination has a mutagenic effect, which is the ability to create new mutations.

These findings suggest that recombination and gBGC are important factors in evolution and that neodarwinism may need to be modified to account for their effects.

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