Lamarcks "DNA methylation enables transposable element-driven genome expansion" without Darwin


We now have number of non-NeoDarwinian explanations of how DNA methylation enables transposable element-driven genome expansion:

  • DNA methylation is a chemical modification of DNA that can silence genes without mutations.

  • Transposable elements (TEs) are mobile pieces of DNA that can insert themselves into other genes. This sudden action counters Darwin's gradualism by slow mutations. 

  • When TEs insert themselves into genes, they can disrupt the function of those genes.

  • DNA methylation can silence TEs, preventing them from disrupting the function of genes without changing the DNA sequence per NeoDarwinism.

  • This allows TEs to accumulate in the genome without causing harm to the organism.

  • Over time, the accumulation of TEs can lead to genome expansion outside of NeoDarwinism.

This process of genome expansion is not dependent on natural selection. In fact, it can even happen in organisms that do not reproduce sexually. For example, some bacteria can acquire new genes by taking them up from their environment. This process, called horizontal gene transfer, can also lead to genome expansion.

DNA methylation is a process that adds a methyl group (CH3) to the cytosine (C) nucleotide in DNA. This modification can silence genes by preventing them from being transcribed. Transposable elements (TEs) are mobile pieces of DNA that can copy themselves and insert into new locations in the genome. TEs are often transcribed, even though they do not encode any proteins as with neo Darwinism.


DNA methylation can suppress the activity of TEs, which can help to prevent them from causing harm. In addition, DNA methylation can promote the expansion of the genome by allowing TEs to insert into new locations without disrupting gene function. This process is called transposon-driven genome expansion.


Transposon-driven genome expansion is thought to have played a role in the Lamarkian evolution of large genomes in plants and animals. For example, the maize genome is about 20 times larger than the human genome, and a large portion of this difference is due to the presence of TEs.

Here are some additional details about DNA methylation and transposon-driven genome expansion:

  • DNA methylation is a heritable modification, which means that it can be passed from parent to offspring. This means that DNA methylation can help to protect organisms from the harmful effects of TEs over generations.

  • Transposon-driven genome expansion is a relatively slow process. It can take millions of years for a genome to expand significantly through this mechanism.

  • DNA methylation is not the only factor that can promote transposon-driven genome expansion. Other factors, such as changes in the frequency of TE transposition, can also play a role.

DNA methylation and transposon-driven genome expansion are two important processes that play a role in the Lamarckian evolution of eukaryotic genomes. 

DNA methylation is a complex process that plays a role in many different cellular processes. In addition to suppressing TE activity and promoting genome expansion, DNA methylation can also regulate gene expression, DNA repair, and cell differentiation.

DNA methylation is a non-genetic (Darwinian) mechanism that can regulate gene expression. It is one of the many ways that organisms can adapt to their environment. In the case of TEs, DNA methylation can help organisms to tolerate the presence of these potentially harmful elements. This allows TEs to accumulate in the genome, which can lead to genome expansion.

Article snippets

DNA methylation enables transposable element-driven genome expansion

2020

Multicellular eukaryotic genomes show enormous differences in size. A substantial part of this variation is due to the presence of transposable elements (TEs)

They contribute significantly to a cell's mass of DNA and have the potential to become involved in host gene control.

We argue that the suppression of their activities by methylation of the C-phosphate-G (CpG) dinucleotide in DNA is essential for their long-term accommodation in the host genome and, therefore, to its expansion

An inevitable consequence of cytosine methylation is an increase in C-to-T transition mutations via deamination, which causes CpG loss

Cytosine deamination is often needed for TEs to take on regulatory functions in the host genome.

TEs are seldom found at promoters and transcription start sites, but they are found more at enhancers, particularly after they have accumulated C-to-T and other mutations

Therefore, the methylation of TE DNA allows for genome expansion and also leads to new opportunities for gene control by TE-based regulatory sites.



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