Looks like, Jumping genes have jumped again to a new conclusion, leading to an astonishing discovery. Jumping genes or transposons are sequences of DNA that move (or jump) from one location in the genome to another. These genes though, constitute the ‘Junk DNA‘ are known to be credited for increasing genetic diversity within the genome throughout evolution.
New research by Washington University School of Medicine in St. Louis have indicated another surprising role, the transposable elements have to play; stabilizing the 3D folding patterns of the DNA molecule inside the cell‘s nucleus. This is contradictory to the belief that jumping genes that move randomly in the genome and are responsible for variation in the genome, can provide stability to the DNA.
Considering the length of DNA (approx. 2m), it has to be compactly packed, to fit into such a small space, it must fold into precise loops that also govern how genes are turned on or off.
“In places where the larger 3D folding of the genome is the same between mice and humans, you expect the sequence of the letters of the DNA anchoring that shape to be conserved there as well”, said Senior author Ting Wang, Ph.D., the Sanford C. and Karen P. Loewentheil Distinguished Professor of Medicine said:
While studying the genomes of mice and humans, the DNA folding patterns of both were studied in detail. The patterns were conserved throughout the evolution but the genetic sequence of the DNA letters establishing these folds was not, because of the jumping genes. Still, the function remains the same, even when the sequence is not the same. And from the research, it was seen that this has happened multiple times over the past 80 million years when the common ancestors of mice and humans first diverged from one another.
A beautiful feature of evolution
The point that a new transposable element can jump anywhere in the genome, and still the functionality of the genome remains the same, even when the sequence gets slightly changed, makes the whole point, pointless, thus, making it redundant. But this redundancy makes the genome stronger. In providing both originality and stability, jumping genes may help the mammalian genome strike a vital balance. For instance, when the basic biological functions required for life remains the same, but with time, the animal can adapt to the changing climate. This poses a beautiful feature of evolution.
Even so, the researchers were careful to distinguish between portions of the genome that hold genes responsible for producing proteins and the rest of the genome. In genes that code for proteins, the genetic sequence and the structure are both conserved, and this study does not contradict that. However, the new research suggests that jumping genes in the non-protein coding areas of the genome follow different rules of conservation than the protein-coding genes.
Function stays the same
After this research, it makes more sense in light of our new understanding of transposable elements — while the local sequence can change, but the function stays the same. The genome is so wide and so deep but we keep the quest on, for many more mysteries to be solved.