A Gene Editing Tool


In this world of rapidly accelerating scientific and technological progress, it has been easy to become blasé about constant media reports of the latest advancements and what they might potentially offer.    In this case and unless you read the scientific journals and columns or watch the BBC ‘Hardtalk’ series you may have missed the fact that the most significant advance in decades has just occurred.  Biochemists now have a universal gene editing tool called CRISPR/Cas9.

Scientists investigating the immune system were studying CRISPR,  a system of DNA sequences in simple organisms that retain snippets of DNA from previously encountered viruses and which are used as a programmable defence system.  Aware that the process would involve genetic manipulation they searched for a mechanism for this and discovered that a protein/enzyme called Cas9 was responsible.  In Cas9 they found 2 elements of RNA that can be changed to match a DNA sequence.  The RNA can then read DNA to search for a matching sequence which, where found, is removed. Cells can then replace the missing sequence.

The scientists then engineered the Cas9 RNA into a simpler form than that found in nature and it is the engineered RNA that is now used as a tool for manipulating genomes.  It is a tool that can be used to alter DNA sequences at will.  Any type of DNA can be edited.   Put simply, scientists can now take any DNA and change it into whatever DNA they choose.  The CRIPR/Cas9 tool is already being used in  laboratories around the world with research progressing at an incredible pace.

The tool can also be used to change human DNA in a way that will be passed on to descendants.  Although it has yet to be used on humans (as far as we know), in the laboratory the tool has aleady been  used to correct the mutation that causes sickle cell anaemia (with great success) by editing the DNA in stem cells.  The scientists expect to eventually be able to eradicate all the suffering that is caused by inherited diseases.

The many realistic expectations of the tool include cures for diseases such as cancer and HIV plus mosquitos that no longer carry malaria.  Current research includes the restoration of extinct species, such as the woolly mammoth.  In fact, the tool could be used to create a human being.


Jennifer Doudna talks about CRISPR/Cas9


As with all scientific and technical advances, there are questions as to whether this will overall be a good thing or a bad thing.  My answer will always be that it depends who controls the application of the technology.  In the right hands this could be of immense benefit to humankind but can we really trust corporations like Monsanto with such a tool.

Additional media:

Biochemist, Dr Jennifer Doudna discusses her work and its implications with Dan Rather in Conversations in Science: CRISPR

Professor Jennifer Doudna explains CRISPR systems in the Rosalind Franklin Lecture at Kings College London

An article by Robert Sanders (UC Berkely) including a video in which Jennifer Doudna talks about the ethics of the process can be seen at the University of California website.