By Zac Warham

Non-coding DNA may be colloquially known as “Junk DNA”, but is it really useless? Non-coding, or “Junk” DNA refers to sections of the genome known as introns. These sections do not code for a protein and so, on the surface, seem to have no use. However, due to ongoing research, understanding is changing to the point where we believe that this “junk DNA” may have some use in the functioning of complex life.

Research has shown that “introns can increase gene expression without functioning as a binding site for transcription factors” (Shaul, 2017). To put it singly, even though introns do not bind to complimentary bases to code for proteins, they still have an effect on how, and to what degree, a gene is expressed. This phenomenon is referred to as “intron-mediated enhancement (IME)” (Gallegos, 2015) . It has been observed that the existence of introns increases the rate of production of mature mRNA in the cytosol. The cause of this may be a higher rate of transcription, a higher rate at which mRNA leaves the nucleus or increased mRNA stability. All of these causes are therefore likely to have been caused themselves by the presence of introns.

Furthermore, it is misleading to refer to “Junk DNA” as “Junk” as instead it would be more appropriate to call it something like “Enigma DNA” as though we are working towards finding it’s true purpose in the genome, we are not yet sure, and so the mystery of what “Junk DNA” does (or doesn’t) do remains, for the most part, an enigma.

Finally, the real nail in the coffin of the theory that “Junk DNA” really is “Junk” is the fact that “Junk DNA” has been highly conserved in organisms throughout millions of years (Dr. Ananya Mandal, 2023). This would suggest that it has undergone positive selection through evolution, if it was unneeded and functionless, then surely the process of evolution would have eradicated this “Junk DNA” once and for all.