The authors explained that seven days after fertilisation, the fertilised egg forms a blastocyst, a ball of 200 cells and OCT4 ensures this blastocyst is formed correctly. "We were surprised to see just how crucial this gene is for human embryo development, but we need to continue our work to confirm its role,” shared Dr Norah Fogarty, the first author of the study.
This is the first time that genome editing has been used to study gene function. Published in the Nature journal on 20 September 2017, the collaborative effort witnessed the participation of scientists from Cambridge and Oxford Universities, the Wellcome Trust Sanger Institute, Seoul National University and Bourn Hall Clinic.
The aim of the study was to understand why so many pregnancies fail (only 12% of fertilised embryos make it to a live birth), and to learn how to improve IVF treatments. To do this, the team first spent a year refining their technique using mouse embryos and human embryonic stem cells before finally working on human embryos.
The embryos used in the study were donated by couples who had undergone IVF treatment and completed their families and wanted their extra embryos to be used for research. The researchers inactivated the OCT4 gene in the DNA of 41 embryos; and following seven days of growth, stopped the embryos and analysed the results.
Dr Kathy Niakan, who led the research, explained that, “one way to find out what a gene does in the developing embryo is to see what happens when it isn't working.” Aside from blastocyst formation, OCT4 is also involved in developing the cells that become the placenta and is also believed to help stem cells specialise into various tissues.
"We have the technology to create and use pluripotent stem cells; but we still don't understand exactly how these cells work. Learning more about how different genes cause cells to become and remain pluripotent will help us to produce and use stem cells more reliably,” elaborated James Turner, co-author of the study.
Study reignited fears about designer babiesAlthough the study was done under a research licence and strict regulatory oversight from the Human Fertilisation and Embryology Authority (HFEA) – the British Government's independent regulator – many scientists are alarmed that approval was given in the first place.
The technology of CRISPR itself has been the cause of much concern for its potential to create made-to-order babies. Yet, as the researchers explained in their report, this is also an opportunity to finally understand exactly how a single cell becomes a complex human. In fact, this alone, has been the main reason scientists have been allowed to manipulate human DNA in a way that could be passed down to future generations.
Nonetheless, Marcy Darnovsky, head of the Centre for Genetics and Society (CGS), a genetics watchdog group, says showing that the technology could be used in this way would "put us into a situation where some children were perceived to be biologically superior to other children.”
Given that in February of this year, the US Government stated that editing DNA in humans could be allowed in certain circumstances, Darnovsky says, "in a world already plagued by distressing levels of inequality, that seems like a very bad idea,"
"We don't want to add ideas that some people are biologically better and some people are biologically inferior to others. That is an idea that has led to horrific abuses throughout history," he elaborated.
Experiment opened doors to further such studiesDespite these valid reservations, the vast majority of the scientific community appears to be supportive of the experiment; especially as it presents implications for R&D in a number of varied areas across health.
One such area is the nutrient medium used in IVF. As embryos release molecules into the nutrient medium in which they grow, it might therefore be possible to use these to work out which embryos are healthiest before implantation.
In addition, the nutrient medium used is based on what works best for mice. Therefore, further studies like this one could help researchers develop formulas better suited to human embryos. According to Dr Ludovic Vallier, study co-author from the Wellcome Trust Sanger Institute, the study could also help “understand adult diseases, such as diabetes, that may originate during the early stage of life.”
CRISPR, which has repeatedly been dismissed as a contender for a Nobel Prize, could in theory, be used to eliminate disease-causing mutations in embryos – and create long-living and disease-resistant plants and livestock.
Previously, in 2015, Chinese scientists have caused outrage when they reportedly attempted to use CRISPR to edit human embryos. And just last month, American scientists announced that they have successfully fixed a disease-causing gene in a human embryo – although this has been continually doubted. MIMS
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