Epigenetics is a fashionable, fascinating area of biology but we don't fully understand it. In a welcome step researchers have documented a previously unknown type of epigenetic modification.
In every cell, DNA uses 4 molecules: adenine, cytosine, guanine and thymine, to code for every protein in your body. Every cell has different requirements at any one time however, and epigenetics allows your body to regulate DNA - activating and silencing specific instructions at any one time.
We still have a lot to learn about epigenetics
Previous work has focused on proteins called histones, which bind to DNA and regulate their bound sequences. Altering these histones is one indirect way of regulating your genes, but the cell also uses a process called methylation to directly alter your DNA; enhancing or dimming activity. Previously, scientists believed this only happens on cytosine bases, but new research suggests that adenine can be methylated as well - although it's much less common.
Around 1 in 10 cytosine bases are methylated in your genome
Cytosine methylation is a common process and relatively well understood, but this discovery is potentially extremely important. Epigenetic alteration is a key aspect of aging, and understanding the field will help us unlock the regenerative potential of stem cells.
A new type of regulation
Adenine methylation is much rarer, occurring around 1700 times. These are well spread throughout the entire genome, but they intriguingly don't seem to affect exons. Exons are the sequences of DNA that code for proteins. The majority of DNA is in fact non-coding and we're still getting to grips with what it's actually there for, but it's likely we have a great deal more to discover regarding DNA regulation and control. This new addition to epigenetics adds weight to that fact.
"These newly-discovered modifiers only seem to appear in low abundance across the genome, but that does not necessarily mean they are unimportant. At the moment, we don't know exactly what they actually do, but it could be that even in small numbers they have a big impact on our DNA, gene regulation and ultimately human health"
The big question now is whether there are even more ways the cell regulates DNA.
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