CRISPR-Cas9: "Ethical catastrophe?"



In March 2015, two groups of scientists warned the scientific community of the possible spin-offs of using a new genome modification tool, namely CRISPR-Cas9.

 

Albert Barrois explains how this new technique was developed:

The first discovery dates back to 1987, with a Japanese team who "reported the existence of a new type of repeated sequence in the genome of a bacterium". The "repeated sequences" were found in numerous bacteria.  They are referred to as "CRISPRs "[1] and the related genes are called "Cas" [2]. They "code the proteins capable of cutting DNA". This is the first stage. Many others focus on the twenty or so years of basic research conducted in this field.

 

2007, 2011, 2012: several articles in Nature or Science celebrate the major stages in the development of “a straightforward tool capable of causing mutations" by targeting a precise sequence: "small RNA sequences specifically form hybrids to DNA and recruit a protein, Cas9, capable of cutting DNA". The technique is developing rapidly and is used "in a small worm, in a fly, a fish, plants and already in human cells".

The latest development in this technique dates back to 2013 and seeks to "introduce specific mutations and even to insert a DNA sequence in the genome". The tool has been tested successfully in mice to "correct a genetic defect such as Duchenne's myopathy". It thus paves the way for correcting mutations in genes that trigger diseases (BRCA1 gene and breast cancer, for example).

 

However, Albert Barrois asks several questions. The first, which is of a scientific nature, focuses on the specificity of this tool: "Small RNA guides" are not specific to a single DNA sequence and can therefore introduce mutations in undesirable places. This risk "will never be completely eradicated".

 

The second question focuses on the ethical problem raised by CRISPR-Cas9: "This method is so simple that it leaves the door wide open for the craziest eugenic approaches". "Who can stop a private clinic (…) from using it to improve the genome?". He ends by posing the following question: will calls by scientists for a moratorium prevent laboratories from "modifying the genome of human embryos?”.

 

 [1] Clustered Regularly Interspaced Short Palindromic Repeats.

 

[2] CRISPR associated genes.


Sources: 

ALbert Barrois, 30.03.2015