"Junk DNA" shapes the embryo without Darwin


Transposable elements (TEs) are mobile genetic sequences that can copy themselves and insert into new locations in the genome. They are found in all eukaryotic genomes, including the human genome. TEs are often thought of as "junk DNA," but they are actually playing important roles in many different biological processes, including early human embryo development.

In early human embryos, TEs are activated and transcribed, which contributes to the regulation of gene expression and the formation of different cell types. For example, TEs have been shown to be involved in the development of the inner cell mass, which gives rise to the embryo proper. TEs are also thought to play a role in the epigenetic regulation of genes, which can influence how genes are turned on and off.

In recent years, there has been growing interest in the study of TEs in early human embryo development. This is due in part to the development of new technologies, such as single-cell RNA sequencing, which have allowed researchers to study the expression of TEs in individual cells. This research has revealed that TEs are not only active in early embryos, but they are also playing important roles in the development of different cell types.

The study of TEs in early human embryo development is still in its early stages, but it has the potential to provide new insights into the mechanisms of embryogenesis. This research could also lead to the development of new therapies for diseases that are caused by TEs.

Here are some specific examples of how TEs are involved in early human embryo development:

  • Endogenous retroviruses (ERVs) are a type of TE that can encode proteins that are involved in the regulation of gene expression. ERVs are activated in early embryos, and they have been shown to be important for the development of the inner cell mass.

  • Alu elements are a type of TE that is abundant in the human genome. Alu elements are transcribed in early embryos, and they have been shown to be involved in the formation of different cell types.

  • Transposase-encoding TEs are a type of TE that encodes proteins that can catalyze the movement of TEs from one location to another in the genome. Transposase-encoding TEs are activated in early embryos, and they have been shown to be involved in the rearrangement of the genome.

The study of TEs in early human embryo development is a rapidly growing field of research. This research is providing new insights into the mechanisms of embryogenesis and the role of TEs in human health.

https://doi.org/10.1016/j.gde.2023.102086

Transposable elements (TEs) and endogenous retroviruses (ERVs) are mobile genetic elements that can insert themselves into the genomes of other organisms. 

Neo darwinism is the gradual accumulation of random mutations. TE's and ERVs involve the sudden movement of "chunks" of DNA or genes via horizontal gene transport (HGT) without Darwin.

TE's and ERVs play a role in evolution outside of neo darwinism in a number of ways.

One way is by disrupting genes. When a TE or ERV inserts itself into a gene, it can disrupt the gene's function, which can lead to changes in the organism's phenotype. For example, a TE or ERV that inserts itself into a gene that controls the development of a particular organ could lead to the organism having a different-shaped organ.

Another way that TEs and ERVs act outside of neo darwinism is by promoting genetic recombination. When two genomes that contain TEs or ERVs recombine, the TEs or ERVs can be exchanged between the genomes. This can lead to the introduction of new genetic information via non Darwinian adaptation into the population.

The role of TEs and ERVs in evolution is still being studied, but it is clear that they can play a significant role in shaping the genomes of organisms. They can disrupt genes and promote genetic recombination and cause rapid adaptation. All of these activities can lead to the introduction of new genetic variation into the population, which can lead to rapid non-Darwinian adaptation.

In addition to the mechanisms mentioned above, TEs and ERVs can also play a role in evolution by influencing the expression of genes. For example, a TE or ERV that inserts itself near a gene can alter the way that the gene is expressed, which can lead to changes in the organism's phenotype.


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