Method for editing embryo DNA at centre of legal war

Washington, United States | AFP | As scientists announced Wednesday they had corrected a disease-causing gene mutation in human embryos for the first time, a legal dispute over who discovered the CRISPR-Cas9 “editing” tool they used, continues to rage.

With the potential to revolutionise medicine and agriculture, the fight over patent rights in the United States potentially involves vast sums of money.

– WHAT? –

Repeatedly mooted as a worthy candidate for the Nobel Prize in Chemistry, the technique allows scientists to remove and replace a faulty sequence on a strand of DNA with pinpoint precision.

The Cas9 protein is used as genetic “scissors” to eliminate the mutated gene, which is then replaced by a corrected version.

The method can theoretically be used to eliminate disease-bearing mutations in still-developing human embryos, or to engineer more nutritious and resilient plants and healthier livestock.

– WHO? –

On the one hand, the technique is claimed by the French-American research duo of Emmanuel Charpentier, affiliated to the Max Planck Institute of Berlin, and Jennifer Doudna of the University of California, Berkeley.

They published a study in the prestigious journal Science in 2012, outlining how they used it to very precisely cut strands of isolated DNA.

In the other corner is Chinese-born American Feng Zhang of the Broad Institute in Massachusetts, who used CRISPR in 2013 to alter cells with a nucleus (eucaryotes) found in plants, animals and humans.

– WHAT HAPPENED? –

Berkeley filed for a patent with the US Patent and Trademark Office (USPTO) in 2012.

Zhang and Broad also applied, using a more costly fast-track procedure. Zhang claimed his application of the technique in eucaryotes was specific and distinct from the more general patent sought by the two women.

The case was challenged by Berkeley, but the US Patent and Trademark Office ruled in Zhang and Broad’s favour, saying the work in eucaryotes had advanced on the foundation laid by Charpentier and Doudna.

Berkeley has lodged an appeal.

In the European Union and Britain, authorities have awarded CRISPR patents solely the Charpentier-Doudna duo.

And in June this year, the Chinese patent office similarly ruled that they qualified to seek sole copyright in that country.