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SPEAKER: Hidden in the natural world around us
are powerful biological tools whose potential scientists are
just beginning to unlock.
For billions of years, bacteria have been under attack
from viruses.
But bacteria developed clever defense mechanisms
to remember these viruses and fight back.
Recently, scientists harnessed one of these natural tools
called CRISPR Cas9 and created a powerful gene editing
technology with the potential to treat human disease.
But Cas9 isn't the only CRISPR tool
with applications for human health.
A team of scientists found that a cousin of Cas9, called Cas13,
can be harnessed to actually detect human disease.
Here's how Cas13 works in its natural environment.
First it hunts for viral RNA using an RNA guide.
When it finds its viral target, Cas13 becomes activated.
In some circumstances, it cuts any RNA
it encounters-- a process termed collateral cleavage.
It is this mechanism that scientists at the McGovern
Broad Institute, and Harvard University
harnessed to create Sherlock, a highly sensitive tool
to detect infectious diseases in humans.
Here's how the Sherlock detection system works.
First, researchers take a sample from a patient
with a possible viral infection, like the flu.
Then they amplify the levels of RNA in it
and add reporters that are sensitive to Cas13.
Then an engineered CRISPR Cas13 is added to the sample.
This Cas13 is programmed with a guide
RNA that is designed to find only virus RNA and bind to it.
When this happens, Cas13 activates its cleaving
mechanism and begins randomly slicing nearby RNA,
including the reporters.
Since each end of the reporter carries a different label,
Cas13 separates these two signatures,
creating a unique signal within the sample.
The sample is then applied to a commercial flow detection
If the sample is negative for flu,
the reporter remains intact and collects at the first detection
If the sample is positive for flu,
it collects at a different location,
making a diagnosis easy to spot.
So easy, in fact, Sherlock can be used in the field
to detect emerging infectious diseases and outbreaks,
like Ebola virus.
Before Sherlock, field samples had
to be refrigerated and shipped to labs with expensive gene
sequencing equipment.
Now Sherlock can be adapted to detect any genetic signature,
even ones associated with cancer in virtually any location.
CRISPR Cas9 and Cas13 are just two examples
of natural biological systems that scientists
have modified to fight genetic and infectious disease.
The question remains-- what other tools
are out there in the natural world just
waiting to be discovered?