22 August 2016
Scientists have managed to record histories in the DNA of human
cells, allowing them to recall past "memories."
The advancement could prove vital for
researchers studying how cells undergo genetic changes that
lead to disease.
The advancement was made by biological engineers at Massachusetts
Institute of Technology (MIT), using the genome-editing system
CRISPR. The system consists of a
DNA-cutting enzyme called
Cas9 and a short RNA strand.
The strand guides the enzyme to a
specific area of the genome, directing Cas9 where to make its cut.
Although CRISPR is well known for its gene editing capabilities, the
MIT team managed to use it for memory storage - the first that can
record the duration and intensity of events in human cells. Such
memories include events such as inflammation.
To encode the memories, the scientists designed guide strands that
recognize the DNA that encodes the very same guide strand.
It's a concept they refer to as
"Led by this self-targeting guide RNA strand,
Cas9 cuts the DNA encoding the guide strand, generating a
mutation that becomes a permanent record of the event.
That DNA sequence, once mutated, generates a new
guide RNA strand that directs Cas9 to the newly mutated DNA,
allowing further mutations to accumulate as long as Cas9 is
active or the self-targeting guide RNA is expressed,"
MIT wrote in a
"By using sensors for specific biological events
to regulate Cas9 or self-targeting guide RNA activity, this
system enables progressive mutations that accumulate as a
function of those biological inputs, thus providing genomically
encoded memory," the statement
The researchers also found that they
could engineer cells to detect and record more than one input, by
producing multiple self-targeting RNA guide strands in the same
Each RNA guide is linked to a specific
input and is only produced when that input is present.
The advancement represents the first
time that scientists have found a way to record such data in human
cells. Although scientists have previously devised ways to record
digital information in living cells, such methods only revealed
whether the event occurred - not how much exposure there was or how
long it lasted.
According to MIT, the new method is most
likely to be used for studies of human cells, tissues, or engineered
The analog memory storage system,
"could also help scientists study how cells differentiate into
various tissues during embryonic development, how cells
experience environmental conditions, and how they undergo
genetic changes that lead to disease," the MIT statement
reads, particularly noting that it could be used to monitor
Genetic Recording with Self-targeting CRISPR-Cas in Human Cells) was published in the journal Science last week.