Biased "mutations" not Darwins "random" mutations causes "change" over time

-


A single nucleotide polymorphism (SNP) is a variation in a single nucleotide that occurs at a specific position in the genome among individuals. Nucleotides are the building blocks of DNA, and there are four different types: adenine (A), cytosine (C), guanine (G), and thymine (T). A SNP can occur when one of these nucleotides is substituted for another at a specific position in the genome.

The percentage of single nucleotide polymorphisms (SNPs) caused by GC bias, AT mutation bias, and DNA polymerase errors are:

  • GC bias: 60-70%

  • AT Mutation bias: 30-40%

  • DNA polymerase errors: <1%

GC bias is the preference of some DNA polymerases to incorporate guanine (G) and cytosine (C) nucleotides over adenine (A) and thymine (T) nucleotides. AT Mutation bias is the tendency of certain mutations GC to AT to occur more frequently. DNA polymerase errors are rare and occur when DNA polymerase incorporates an incorrect nucleotide into the DNA sequence.

GC bias is the most common cause of SNPs because GC-rich regions of the genome are more likely to undergo DNA replication than AT-rich regions. AT Mutation bias is also a common cause of SNPs, but it is less common than GC bias. DNA polymerase errors are the least common cause of SNPs because DNA polymerase is a very accurate enzyme. Random DNA polymerase errors are thought to provide the variation for neo Darwinism.

It is important to note that the exact percentage of SNPs caused by each of these factors can vary depending on the population studied and the genomic region examined. For example, GC bias is more common in human populations than in other species, and it is more common in coding regions of the genome than in non-coding regions.


The percentage of single nucleotide polymorphisms (SNPs) caused by GC bias, mutation bias, and DNA polymerase errors is estimated to be around 80-90%. This challenges neo-Darwinism in a number of ways.

First, it suggests that the vast majority of mutations are not random and not directed by natural selection. This is in contrast to the neo-Darwinian view that random mutations (random DNA polymerase errors, <1%) are the driving force of evolution, and that natural selection acts to weed out harmful mutations and preserve beneficial ones.

Second, NeoDarwinian random mutations make it difficult to explain the complexity and diversity of life. Neo Darwinism posits that evolution occurs through a gradual process of accumulating small, random mutations. If most mutations are random and mostly harmful, it is difficult to see how this process could lead to the development of complex and sophisticated organisms.

Third, the high rate of biased mutations makes it difficult to distinguish between adaptive and non-adaptive evolution. Neo Darwinism predicts that adaptive evolution, which is the process by which organisms develop new traits in response to environmental changes, is driven by natural selection. However, if most mutations are biased it is difficult to see how natural selection could distinguish between adaptive and non-adaptive mutations.

Here are some specific examples of how the high rate of biased mutations challenges neo darwinism:

  • The existence of junk DNA. Neo Darwinism predicts that 98% of DNA sequences are Junk DNA that have no function, and that natural selection will eliminate any sequences that are not beneficial. However, recent studies have shown that neo darwinism has not removed this junk DNA. This suggests that natural selection is not as effective in eliminating harmful mutations as neo darwinism predicts.

  • The existence of genetic diseases. Neo Darwinism predicts that natural selection will eliminate harmful mutations from the population. However, there are many genetic diseases that are caused by mutations that have been passed down from generation to generation. This suggests that natural selection is not able to eliminate harmful mutations.

  • The rapid evolution of antibiotic resistance. Neo Darwinism predicts that adaptive evolution is a slow process that occurs over many generations. However, the rapid evolution of antibiotic resistance in bacteria suggests that adaptive evolution can occur much more quickly than neo darwinism predicts. This suggests that biased  mutations can play a significant role in adaptive evolution.

Overall, the high rate of biased mutations (GC bias & AT mutation bias) challenges the neo darwinian view of evolution in a number of ways. It suggests that the vast majority of mutations are not directed by natural selection, that biased mutations can play a significant role in both adaptive and non-adaptive evolution, and that natural selection is not always able to eliminate harmful mutations.

The high rate of biased mutations is a significant challenge to neo darwinism, and it suggests that the theory may need to be modified or replaced in order to account for the role that biased mutations play in evolution.

Ref:

Google Scholar gBGC

Google Scholar Mutation bias

Google Scholar DNA polymerase mutations

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

ERVs and Common Descent: A Reassessment in Light of Recent Findings

-
Image
Endogenous retroviruses (ERVs) have long been considered strong evidence for the common descent of humans and chimpanzees. These remnants of ancient viral infections, embedded in the genomes of both species, were once thought to be non-functional "junk DNA." The premise was that the shared presence of these seemingly random insertions in corresponding genomic locations could best be explained by a shared evolutionary history. However, recent research, such as the "Switching Sides" article published in May 2021, has challenged this assumption by demonstrating that ERVs play a functional role in the development of the human embryo and immune system. This discovery raises questions about the validity of using ERVs as primary evidence for common descent. The Traditional Argument for Common Descent The traditional argument for common descent based on ERVs rests on the following points: Random Insertion: Retroviral insertions are thought to occur randomly in...
Read more