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This DNA has lumps

By David, 26 April 2018 News

Image through a microscope, magnifying spiral strands and shapes on a blue background

The y-shaped dye attaches to the i-moifs, shown in green. Image: Chris Hammang

Inside most cells in your body, there’s a copy of your entire genetic code. It contains instructions that help build and maintain your body. If you imagine DNA in its double helix form, it’s a beautiful, perfect package. Except, maybe DNA doesn’t always look so perfect after all. A team of Australian researchers just discovered that DNA in living cells has lumps.

DNA’s most common form is a double helix, where two strands spiral around each other. Each strand is made of small chemical units called bases, and the bases in the two strands match. When one strand has base A, the other has base T. When one strand has base C, the other has base G.

In the 1990s, scientists discovered that they could get one strand of DNA to stick to itself by adding chemicals. There were Cs that connected with other Cs rather than with Ts. This formed a strange lump or knot known as an i-motif. However, they weren’t sure if these lumps ever formed in nature.

Recently, a team from Sydney went looking for i-motifs. They first developed a dye, made from fragments of immune system proteins. This dye glows under the right lighting conditions, but only when near an i-motif.

They injected the dye into living human cells and put them under a microscope to see what was glowing. They found several bright spots inside each cell, indicating there were i-motifs present. Over time, the bright spots faded and new ones formed. The i-motifs were disappearing and reforming all the time!

The team think that these i-motifs could be one way the body turns certain genes on and off, but we can’t be certain. More work needs to be done, but it’s possible these knots might be quite common. These little lumps might even be in your DNA!

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