Unlocking the mystery of what makes us human

The creation of synthetic, human-like embryos is an awe-inspiring scientific breakthrough.

Norman Lewis

Topics Science & Tech UK

Truly groundbreaking advances in science are sadly rare occurrences. So when they happen, we should celebrate them. The announcement that scientists have successfully created synthetic embryos from stem cells is one such advance.

The breakthrough was announced earlier this month in the plenary address at the International Society for Stem Cell Research’s annual meeting in Boston. Professor Magdalena Zernicka-Goetz, from Cambridge University, revealed that it was now possible to create ‘human embryo-like models’ by reprogramming embryonic stem cells. These synthetic embryos sidestep the need for eggs or sperm.

This breakthrough was built on the work carried out last year by Zernicka-Goetz’s team and a rival group at the Weizmann Institute in Israel. Both groups developed stem cells from mice that self-assembled into early embryo-like structures. In April this year, researchers in China also managed to create synthetic embryos from monkey cells.

The development of ‘human embryo-like models’ is a massive advance on the development of earlier embryo-like structures. Although they’re not actually human embryos, they will still deepen our understanding of human biology. Above all, they will allow us to obtain critical insights into a window of early human development that, until now, has primarily remained a ‘black box’. (This is partly because of the widely accepted 14-day rule, which requires that human embryos will not be kept alive in vitro longer than two weeks after fertilisation or the stage of development that is equivalent to when embryos finish implantation.)

These models unlock this ‘black box’. They have been developed from a single embryonic stem cell to reach the early stage of gastrulation – the development milestone that sets up the primary axes of the body. There is no beating heart, no gut, nor even the beginning of a brain. But remarkably, these model embryos show primordial cells, the precursor cells of egg and sperm – the source of life. No wonder Zernicka-Goetz described this development as ‘beautiful’.

It certainly opens up incredibly rich avenues of research that will be vitally important for people affected by infertility or genetic conditions. It promises to advance our understanding of human development, disease and reproduction. It will also improve established reproductive technologies, while opening up new drug-testing and development possibilities. Make no mistake, synthetic embryos could impact and improve the lives of millions of people.

At this point, the chances of these human embryo-like models developing into living creatures are extremely low. This really is not about ‘lab-grown babies’. Nevertheless, Cambridge University has already launched a Governance of Stem Cell-Based Embryo Models (G-SCBEM) project, led by Cambridge Reproduction in partnership with the fertility charity, Progress Educational Trust (PET). The aim is to develop a control framework for this research.

These embryos still necessarily pose ethical and philosophical questions. For a start, what, in a philosophical sense, are these ‘human embryo-like models’? Professor Zernicka-Goetz argues that, while they may look like embryos, complete with a three-dimensional structure, ‘they’re not embryos’. Sandy Starr, deputy director of the PET, says that while that question is at this point unanswerable, ‘which form of life applies to reproductive materials is a very rich area for debate’.

Indeed, the research has already sparked controversy, with scientists and ethicists debating how we should treat these not-quite-human embryos. For example, should they be subject to the same regulations as human embryos, complete with the 14-day rule? These questions touch on the biggest question of all – namely, what exactly makes us human?

The development of these synthetic embryos and the questions they have raised should be welcomed. The history of science and medicine has repeatedly forced civilisations to confront difficult existential questions about life, belief and meaning. The development of a synthetic, embryonic lifeform is no different.

The potential here to expand human understanding and transform human life is awe-inspiring. Let’s embrace it.

Dr Norman Lewis is managing director of Futures Diagnosis and a visiting research fellow of MCC Brussels.

Picture by: Getty.

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Topics Science & Tech UK


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