Fascinating genetics: # The Retrotransposons

Greetings!

I got something amazing for you today, at least according to me. It took me about 3 years into a 5 year long education in biochemistry & engineering before i happened to stumble upon this fascinating genetic element. I ll keep it short!

The Retroransposons

Retrotransposons are a strand of DNA with the capacity to copy and paste it self in order to multiply and become more abundant in our genome. The process is actually pretty simple and straightforward, utilizing the standard pathways for transcription, meaning it is turned from DNA in our genome to RNA. But during translation, when the RNA is suposed to become a mature protein, it is also reverse transcribed by an enzyme called a reverse transcriptase, making DNA once again.

Retrotransposon pathway

The newly synthesized DNA is the integrated into the genome, making it more likely to be turned into an actual protein later on.

The reverse transcriptase synthesizes a new DNA strand directly on the RNA, it is then cleaved and pure DNA is produced in the next round of synthesis.

Retrotransposons are nothing uncommon in eukaryotic cells, the cells of animals and plants. In fact, maze for an example has extremely high abundance of retrotransposon generated DNA, as much as 50-75% of its genome, amazing!
This is an mechanism used by our cells or viruses to incorporate new DNA into an organism or simply make it more abundant.
Imagine moving to a desert zone from a cold climate, after generations, your genome might have higher abundance of genes coding for heat resistant proteins and more pigment!

This also applies on what you eat, which puts stress on your cells to metabolize or detox whatever you take in. Eating a lot of meat would require more proteases to digest the proteins, making it more likely that they are inserted into the genome. You truly are a result of your environment and eating habits.
Retro viruses can also act as an retrotransposon, called LTR retrotransposon by modifying its initial genome, deleting sequences made for movement outside cellular environments, turning it into a retrotransposon.

If the virus is inserted in to our germ line DNA it can lead to the DNA being stabilized in the gene pool of the host population and spreading!It is approximated that 5-8% of humans DNA consists of inserted DNA from viruses, the lowest estimate i´ve seen is 1 % which is simply fascinating! In total the human genome is made up of around 40% retrotransposomal DNA, mind blowing! The study of the underlying mechanisms explaining how the host genome has co-evolved with retrotransposomes is still just getting started and has long to go,

It is also theorized that the copy and pasting of DNA can be traced backwards and work as further proof of the evolution theory, now if u believe in that stuff :)
I Hope that you enjoyed this little read, i sure did when checking into it and i think it is a good example of showing how dynamic our genome can be.
At last a picture of our current genome composition after millions of years of evolution alongside retrotransposons.

Genome composition
P.s Over 99% of our retrotransposonal DNA is inacvite so dont worry about changning over night!

Figure 1
Figure 2
Figure 3
Figure 4