Calum MacKellar: Concerns over ability to edit a human life

Brave New World highlights the spectre of eugenics which still colours attitudes to genetic work. Picture: Contributed

Since the entire genetic code of a human being was deciphered in 2003, scientists have been in possession of the genetic instructions for every component of every cell in the body.

But within these instructions, errors or changes to genes may arise which can result in serious health disorders. Despite being aware of these mistakes, there was no easy way to edit and address these genetic errors until 2013, when a group of scientists in California discovered the CRISPR (clustered regularly interspaced short palindromic repeats) technique. The procedure acts like a pair of molecular scissors with a sort of satnav which guides the scissors to cut or replace genetic material at a precise point in a gene. Because of this, it is called gene editing and is easier, cheaper and more realistic than ever before.

The image of a future where cancer can be cured by a course of drugs, Alzheimer’s can be easily prevented and genetic diseases can essentially be bred out of society is naturally appealing. So why are scientists even hesitating in making this image a reality by employing a technology like CRISPR? Does society not have a responsibility to humankind to use this new discovery immediately?

In order to answer these questions, it should be noted that there are serious safety, ethical and philosophical concerns why a technology like CRISPR, which makes genetic changes to human beings, needs to be approached with caution.

Though it may be easier to use and more precise than previous gene editing techniques, it is still far from perfect. One of CRISPR’s present limitations is that the wrong part of the gene may be edited. This was highlighted in April this year when Chinese gene-function researcher Juniju Huang used CRISPR to edit the genetic makeup of 86 human embryos. Of the 71 embryos that survived the experiment, 54 were tested revealing that only 28 were successfully edited, and only a fraction of these contained the replacement genetic material. The experiment confirmed the doubts of many scientific observers – CRISPR is not yet ready to be used for human application.

In fact, Jennifer Doudna, the American scientist credited with CRISPR’s discovery, has publicly called for a moratorium on some uses of the technology, stating she feels that it is “critical to initiate a public discussion of the appropriate use of this technology” and to call for a voluntary ban on human inheritable gene editing for clinical applications at the present time.

There are others who want to take this message a step further and prevent technology like CRISPR from ever being used on humans. Altering the human genetic heritage is not only permanent for that individual; it is inheritable and alters the genetic makeup of future generations. The long-term effects of such action are still very much unknown.

In an interesting juxtaposition, another argument against gene editing is that it removes the genetic lottery of reproduction. If it is possible to alter a person’s genes to remove and change attributes such as predisposition to disorders, it is also possible to change just about any other attribute. For example, if individuals have a family history of degenerative vision and they want to guarantee that their child will not inherit the disorder, scientists could edit that gene to ensure their children are born with perfect vision.

However, they could also edit the genes that determine the colour of a child’s eyes together with just about any other physical feature.

Ever since the writer Aldous Huxley published his science fiction book Brave New World in 1932, the world at large has feared the spectre of eugenics which promotes a superior genetic heritage. It used to seem a long way off (the book is set in the year 2540) but technologies like CRISPR have brought the future a whole lot closer. CRISPR may be too immature to use for altering human genes right now but with some of science’s best minds working day and night to iron out the problems it is very likely that progress will be forthcoming.

So before one gets to that point, serious and inclusive public ethical discussion is necessary to determine if society should use technologies like CRISPR, just because it can.

• Dr Calum MacKellar is director of research at the Scottish Council on Human Bioethics, 15 North Bank Street, Edinburgh EH1 2LS

• He will be discussing these issues in greater detail as part of a panel discussion on the ethics of gene editing at the CRISPR Summit (www.crisprsummit.com) in London on 9 December.