© Adam Diehl
Chromatin loops are important for gene regulation because they define a gene's regulatory neighbor-hood, which contains the promoter and enhancer sequences responsible for determining its expression level. Remarkably, transposable elements (TEs) are responsible for creating around 1/3 of all loop boundaries in the human and mouse genomes, and contribute up to 75% of loops unique to either species.
Chromatin loops are important for gene regulation because they define a gene's regulatory neighbor-hood, which contains the promoter and enhancer sequences responsible for determining its expression level. Remarkably, transposable elements (TEs) are responsible for creating around 1/3 of all loop boundaries in the human and mouse genomes, and contribute up to 75% of loops unique to either species.
Until recently, little was known about how transposable elements contribute to gene regulation. These are little pieces of DNA that can replicate themselves and spread out in the genome. Although they make up nearly half of the human genome, these were often ignored and commonly thought of as "useless junk," with a minimal role, if any at all, in the activity of a cell. A new study by Adam Diehl, Ningxin Ouyang, and Alan Boyle, University of Michigan Medical School and members of the U-M Center for RNA Biomedicine, shows that transposable elements play an important role in regulating genetic expression with implications to advance the understanding of genetic evolution.
Transposable elements move around the cell, and, unlike previously thought, the authors of this paper found that when they go to different sites, transposable elements sometimes change the way DNA strands interact in 3-D space, and therefore the structure of the 3-D genome. It appears a third of the 3-D contacts in the genome actually originate from transposable elements leading to an outsized contribution by these regions to looping variation and demonstrating their very significant role in genetic expression and evolution.
University of Michigan, " Transposable elements play an important role in genetic expression and evolution" at Phys.org
Comment: Transposon activity was not always viewed so favorably:
- Parasites Ready To Jump
- Maelstrom Quashes Jumping Genes
- Storm of 'Awakened' Transposons May Cause Brain-Cell Pathologies in ALS, Other Illnesses
Attitudes are shifting, albeit slowly and reluctantly. The author's question is valid. Why is it so hard to believe that just because science doesn't understand the reason something exists, it assumes there is no purpose to it. Nature makes no waste: