Two major recent advances have been responsible for a veritable revolution in medical research, making it possible to change the genetic make-up of the individual. The first one was the elucidation of the human genetic map (the human genome), and equally important, the development of techniques that make genetic analysis a relatively simple and rapid procedure, to the extent that those who are interested in their genetic background can now get themselves analysed for an affordable amount of cash.
The second major advance has been the development of techniques that allow manipulation of the genome, including cutting at very specific sites, using enzymes (referred to as ‘CRISPR’). This has led to the ability to search for and delete abnormal genes, which can be replaced by a brand new healthy gene, an advance described by The New York Times as “one of the most monumental discoveries in biology”. (See: A Crack in Creation: The New Power to Control Evolution, by Jennifer Doudna & Samuel Sternberg, The Bodley Head, London, 2017).
So is this science fiction or has it been shown to work in practice? And if it does work, why can’t we start removing disease-related genes and replace them by normal ones, thus ridding the world of the load of genetic disorders we are subject to? That the technique works there is no doubt. Many laboratories around the world are furiously working on this issue and many have succeeded in altering genes, both from animals as well as from humans. The techniques have been well established and ready to go. They have been used to eliminate certain harmful genes from patients with blood disorders, muscular diseases and even to render the body resistant to viral attack.
The list of genetic disorders is a long one, but unfortunately to eliminate these one has to start with a modification of the embryo genes, which immediately raised serious ethical problems. Genetic modification of human embryos was first reported a couple of years ago, in 2015, by Chinese scientists, and since then, many other reports from Europe and US have confirmed this.
Altering germ cells results in changes that become inherited
Genetic manipulations involving the embryo result in changes of all cells of the body, which include both the body cells (so-called ‘somatic’ cells, such as heart, muscle, brain, etc.) as well as reproductive cells (the germ cells, i.e. sperm and ova). While there are no major ethical objections to altering somatic cells, altering the germ cells results in changes that become inherited from one generation to the next, and thus spread throughout the whole population.
While the public finds it difficult to understand what’s wrong with eliminating a disease-producing gene from the human gene pool, there have been many objections to gene alterations in the embryo, particularly in view of the fact that any alterations of the genetic make-up can give rise to long-term complications that are not immediately obvious, but which take years to become recognised.
It has also been frequently argued that what starts as an advance for a very laudable aim, like treatment or prevention of disease, can become applied to psychosocial traits like body appearance, intelligence and other conditions which are not directly related to health issues.
Current regulations, where they exist and allow work on embryos, such as in the UK or the US, clearly forbid allowing an edited embryo to continue to develop into a baby. Government funds for such research have been restricted in the US for several years.
However, while bodies like the National Academies of Science and Medicine emphasise the need for stringent oversight of such research, they admit that “edited human embryos hold promise for the prevention of the many serious genetic disease for which there are no treatments”.
Society as a whole, and not just scientists, has the right as well as the obligation to ensure that novel scientific discoveries will not become a threat to the very society in which they live. But society cannot engage in such discussions unless they are reasonably well-informed in good time, before the horse has bolted.
mnc25@optusnet.com.au