Research in the new gene-editing technology CRISPR has raised many red flags and ethical dilemmas as its full capabilities prove to be more than what was thought previously possible. It is used by bacteria to combat viral infections, but now scientists have repurposed it to keep records of a given bacteria’s environmental conditions, which could have significant applications to accurate chronicling of biological changes. Scientific American’s article, “Bacterial ‘Tape-Recorder’ Could Keep Tabs on Bodily Function” outlines how CRISPR “is a DNA sequence that makes and keeps a genetic record of viruses the bacterium encounters, commanding it to kill any that try to reinfect the bacterium or its descendants”. This natural function of bacteria, though, can be manipulated so that instead of exclusively accounting viral encounters, any environmental abnormality can be captured by CRISPR. More specifically, the bacterial mechanism would sense a special signal from a change in its surroundings and create trigger DNA, which, according to the U.S. National Library of Medicine, is a noticeable sequence of DNA from the invaders, which could be used to identify what exactly caused the change.

Applications of this technology today are far-reaching. This technology can be theoretically used to measure contaminants in fresh water or saltwater, or the nutrient levels in topsoil, but the predicted first application will be in monitoring bodily function in humans, and other animals. Digestion problems seem likely to be the first human system monitored with this new tool. Fructose Malabsorption is a digestive disorder which results in high levels of fructose sugar remaining in the digestive system. This disorder results from damaged intestines, normally from serious infection. Sugar levels in the digestive tract can now be monitored precisely by using this application of CRISPR in Escherichia coli cells (bacteria which are naturally found in the human digestive system). The record of sugar can identify specific problems diseased patients, after the E. coli cells are recovered from a patient’s feces, and cause them no harm in the process.

This tool is not without its drawbacks. It is reported that millions of modified bacteria need to be placed in a given system to have an accurate reading of environmental surroundings, and these bacteria have to be in the region of interest for at least six hours. The magnitude and duration of this prospective tool leave much to be desired as initial costs would be enormous, and other limitations, which can only be found through proper testing, remain unknown. In all, this advanced tool still seems applicable for now on only a small scale, but it is an example of CRISPR as a tool for good, and shows much hope for the future.

Escherichia coli bacteria which can be modified with CRISPR to become a “tape-recorder” of the human digestive system

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