For The First Time, Scientists Find a Way to Make Targeted Edits to Mitochondrial DNA - ScienceAlert

Most cells in your body come with two genetic libraries; one in the nucleus, and the other inside structures called mitochondria - also known as the 'powerhouses of the cell'.

The molecular foundation of this revolutionary gene editing tool is a toxin called DddA, secreted by the bacterium Burkholderia cenocepacia to sabotage other microbes when competition over resources turns serious.

To get around this, another research team from the Broad Institute of MIT and Harvard combined their code-swapping deaminase with CRISPR technology, which entails using an RNA template to identify the sequence and then using enzymes to unzip the strands and make changes.

Fortunately, DddA had a unique talent for making changes to both DNA strands, opening the way to ditching CRISPR – and its bulky RNA template – in favour of alternative methods for targeting the sequence you want to change.

Teamed up with DddA, a specially crafted TALE enzyme can find a target sequence inside mitochondria and turn any cytosine it finds into a uracil, which will later transform into a similar DNA-specific base called thymine.