In an Exclusive Interview, Sir Ian Wilmut Discusses Genetic Engineering, His Recent Parkinson’S Diagnosis And, of Course, the Most Famous Sheep in the World

THE BIOMEDICAL SCIENCE 18 SCIENTIST Dolly the sheep

In an exclusive interview, Sir Ian Wilmut discusses genetic engineering, his recent Parkinson’s diagnosis and, of course, the most famous sheep in the world. SCIENCE THE BIOMEDICAL Dolly the sheep SCIENTIST 19

t’s important to “be ambitious!” Wilmut was awarded the Lord Lloyd of Frostie and Tracy, respectively, just a On the eve of the IBMS Congress Kilgerran Prize “for developing and using few of the highlights of a distinguished 2019, this is the advice to biomedical embryo manipulation techniques in farm scientific career which he reflects on scientists considering a career in animals, leading to many potential uses in this exclusive interview for research from the pioneering lead in bio-medicine and livestock breeding”. The Biomedical Scientist. scientist behind Dolly the sheep, While Sir Ian’s 2008 knighthood Professor Sir Ian Wilmut. “There is recognised his contribution to Early days almost no value in repeating work “revolutionising biology through the “I was born that has already been done, provided that cloning technique which underpins the at Hampton the Idesign and technical procedures were science of stem cell technology” and for Lucy, near appropriate,” he continues. “So, consider his “outstanding” commitment to Warwick, carefully what ideas arise from recent bringing the benefits of basic science to in 1944 and raised work and develop new hypotheses.” medical treatment, he “stressed that it in Coventry ‒ my This approach has borne scientific was a recognition to be shared by his parents were fruit for embryologist Sir Ian, who was research colleagues.” teachers ‒ until I was six, described by US senator Tom Harkin as Although forever associated with Dolly when we moved to Shipley, “one of the true trailblazers in human the sheep, Sir Ian’s achievements also Yorkshire. Aged 10, my first history”. For example, in 1998 (then) Dr include bovine and ovine firsts with career choice, inspired by a SCIENCE THE BIOMEDICAL Dolly the sheep SCIENTIST 21

merchant navy captain friend of my such as cows and sheep, as Wilmut later grandfather, was to be a seafarer, but that wrote, “an entirely novel role and was thwarted with the discovery that I’m convert them into living drug factories colour blind.” to make the human proteins factor VIII Wilmut’s love of the outdoors led him and factor IX used to treat haemophilia, to study agriculture at the University of and the enzyme AAT (alpha-1 antitrypsin) Nottingham, “which is where, my interest used to treat lung disorders, such as in embryology began”, he recalls. “After cystic fibrosis.” graduating, I went to the University of Cambridge to undertake my doctoral Tracy thesis at Darwin College, researching the The basis of “pharming” was the freezing of boar semen. I worked at the introduction of a human gene into an Agricultural Research Council’s Unit of animal embryo, which could be Reproductive Physiology and Biochemistry, The prevalent transferred to a surrogate host that would Cambridge, alongside a pioneer of animal give birth to a transgenic animal; a reproductive science Professor Chris Polge, view of scientific process, which Wilmut recalls was who had shown in the 1950s how glycerol “hopelessly and maddeningly inefficient.” can protect frozen cells.” research favoured a But nonetheless the feasibility of the Addressing the challenge of freezing utilitarian approach technology was established at Roslin, semen that would retain viability upon when six transgenic sheep were produced thawing demanded a systematic approach over fundamental, by microinjection of DNA into early that accommodated many variables embryos. A Scottish blackface transgenic associated with the process. Adopting ‘blue sky’ thinking sheep named Tracy was born in 1990: a similar stepwise strategy later paid “Tracy’s milk “contained 35 grams of AAT dividends for Wilmut and colleagues per litre,” Wilmut explains, “and she was in relation to cloning. Roslin probably the world’s most famous sheep In 1970 Wilmut reported that frozen In 1973 Wilmut moved north with his before Dolly arrived.” and thawed boar semen in a yolk-glucose- family, having been appointed to the glycerol diluent achieved an 83% Animal Breeding Research Organisation Megan, Morag and Dolly fertilisation rate when deposited directly (ABRO), located on the southern outskirts The creation of Dolly was not the into the oviducts. of Edinburgh, and which in 1993 became primary objective of Wilmut’s team. the Roslin Institute, now part of the Rather, it stemmed from an idea that Frostie University of Edinburgh. occurred to him while addressing the “By 1971 I had completed my doctorate “At that time the prevalent view of inefficiencies of transgenic technology. but continued working with Chris Polge, scientific research favoured a utilitarian As he wrote: “First take stem cells from this time on cattle, trying to prevent approach over a fundamental, ‘blue sky’ an early sheep embryo, multiply them to embryo-damaging ice crystals forming thinking one,” says Wilmut. “This was, in form millions of cells, then add DNA during cooling, and before embryo my view, a misguided attitude because to those cells and select only transfer,” says Wilmut. “I established the fundamental research tends to make the ones in which the optimal cooling rate that prevented ice bigger advances, even if they are applied process had succeeded crystals forming, and we were the first to less effectively. It is critical to have both for the use in cloning successfully freeze a calf embryo, thaw it fundamental understanding and efficient ‒ nuclear transfer ‒ and transfer it to a surrogate mother.” use of the new understanding if we are to to make animals.” The world’s first “frozen calf” ‒ named make the best possible progress.” With the birth Frostie ‒ was a Hereford-Friesian cross. Progress in molecular biology led of the Welsh Wilmut says: “Frostie’s birth in 1973 was Wilmut to consider how genetic Mountain sheep filmed by a Dutch television crew. This engineering could be applied to improve Megan and Morag in also led to my first experience of dealing the performance of farm animals as the June 1995, Wilmut’s with the media, when I had to give a live era of so-called “pharming” unfolded. team had shown that television interview on the BBC news.” The idea was to give farmyard animals, viable animals could be THE BIOMEDICAL SCIENCE 22 SCIENTIST Dolly the sheep

generated the view that once a about research with animals,” Wilmut when animals9 could be cell had acquired a says. “But it was certainly true that there nuclei from generated with particular tissue type was far more interest following the birth nine-day-old nuclei from it could not be changed, of Dolly. Anticipating that this would be partly nine-day-old certainly not by a single the situation, Roslin Institute and our embryonic cell differentiated protein, nor to a cell type collaborators PPL Therapeutics arranged embryonic sheep cells from a different germ layer. for a key member of the team Keith that had been maintained It was only following the Campbell and I to receive training from by in vitro cell culture introduction of several carefully two former BBC employees. There was no were transferred into selected transcription factors doubt that this helped us cope with enucleated oocytes. that precise change occurred in some different styles of interview.” “Significantly we had established the cells. In some cases, from one germ layer The training paid off, because Wilmut’s important role of the cell cycle ‒ more to another.” contributions have enhanced the cloning specifically, the induction of quiescence debate while avoiding hyperbole. For ‒ in enabling partly differentiated cells The ethics of cloning example, Philip Kitcher reviewing Gina to be reprogrammed,” Wilmut points out. The global impact of Dolly’s birth changed Kolata’s Clone: The Road to Dolly and the Following Megan and Morag’s births, in the scientific landscape, but also raised Path Ahead (1997) for the London Review which embryonic cells had been used for ethical issues. Was this an unexpected of Books lists the “excellent reasons nuclear transfer, we had confidence in challenge? “In my experience there have to celebrate Dolly’s birth as an event the possibility of cloning an adult.” always been some people who protested of scientific importance. They do not

Lamb 6LL3, better known as Dolly ‒ whose embryo was derived from the mammary gland of a Finn Dorset ewe and transferred to a Scottish Blackface ewe recipient ‒ was born on 5 July 1996, the first time that a mammal had been cloned from an adult cell. Dolly’s birth succeeded after 276 previous attempts had failed and was both a tribute to the high degree of technical expertise needed ‒ including the demanding hand-eye coordination of microscopic surgery ‒ and to patient teamwork, sometimes of military precision; for instance, when it came to recovering ewes’ eggs at various times of the day. The demonstration by Wilmut’s team that differentiated adult cells contain all the genetic information needed to form a whole organism and that oocytes can potentially be re-programmed somatic cell nuclei has revolutionised biology and its applications to the treatment of disease. “The most important effect of the Dolly experiment,” observes Wilmut, “was to make biologists think differently. Physiologists had developed SCIENCE THE BIOMEDICAL Dolly the sheep SCIENTIST 23

underwrite Kolata’s claim that it changes potential person. To me, using that Using that our understanding of what it is to be embryo as the basis for developing human. Overstatement of this kind differentiated cells in a tissue culture dish embryo as the contrasts sharply with the modesty and is no different than transplanting the good sense with which Ian Wilmut has organs of a dead person into a living one. basis... is no spoken about his achievement.” Most people are now comfortable with These were apparent when Wilmut, that.” Wilmut is clear, however, in his different than contemplating cloning technology, wrote opposition to human cloning. that the idea of producing human cells to transplanting treat diseases like Parkinson’s, type 1 Dolly’s legacy diabetes or AIDS was controversial Social anthropologist Professor Sarah the organs because of the need to produce a human Franklin has noted: “Dolly is the viable embryo from which you could then derive offspring of a complex scientific lineage of a dead person “stem cells” in vitro: “The controversial in which agriculture, medicine, into a living one. point is whether that embryo is a human embryology, and reproductive physiology being, or only a ball of cells with human [has] long been combined in the service potential. The ‘embryo’ would comprise of both extending basic science and about 250 cells, but with almost no producing new clinical applications.” differentiation into cells with specific By 2002, however, despite Wilmut’s functions… [the embryo] is only a team demonstrating the developmental plasticity conferred by adult somatic cell nuclear transfer, they had acknowledged that relatively little was known about the molecular events occurring within hours of nuclear transfer, but predicted that “[a] new era of developmental biology and regenerative medicine awaits”. This was heralded by a development descended from the pioneering work which led to Dolly’s creation: in 2006 a major breakthrough in stem cell research occurred when Takahashi and Yamanaka reported the generation of induced pluripotent stem cells (iPSCs) by using a retrovirus to deliver four reprogramming transcription factors into adult mouse fibroblasts. Embryonic stem cells (ESCs) and iPSCs are pluripotent ‒ capable of differentiating into cell types from all three germ cell layers (ectoderm, mesoderm, and endoderm) ‒ so what advantages are conferred by using iPSCs over ESCs? Ethical reservations over ESCs, and their limited supply have constrained clinical application, and these, combined with safety concerns in relation to immune rejection of ESCs, mean that Takahashi and Yamanaka’s innovation represents a THE BIOMEDICAL SCIENCE 24 SCIENTIST Dolly the sheep

change of research emphasis. For example, in December last year With iPSC technology a CRM team led by Dr Tilo Kunath successfully translated from developed PD-resistant dopamine murine to human fibroblasts, neurones which could improve cell researchers can “generate disease- therapies for the disease. Cell replacement specific and patient-specific iPSCs for therapy is an emerging treatment for modelling human diseases, drug PD, and laboratory-generated midbrain development and screening, and dopaminergic neuronal precursors can individualized regenerative cell therapy”. mature into functional dopaminergic Thus genetically matched iPSC lines can neurons when transplanted into pre-

be generated from patient cells in vitro and FAILED clinical models of PD. But trials have differentiated into affected cell types, shown that transplanted grafts in PD AFTER

effectively providing a “disease in a Petri HAD are prone to toxic Lewy body formation, dish” model. typical of PD brain cells. Kunath’s team Such models allow researchers to gain used gene editing technology to delete unique insights into the disease, for which the SNCA gene ‒ associated with Lewy

new disease-specific drugs could be SUCCEEDED body formation ‒ and found that this devised. For instance, drugs to prevent the conferred a measure of resistance to Lewy death of medium spiny neurons in patients pathology: cells that had been gene- suffering from Huntington’s disease. edited did not form the toxic clumps, What was Wilmut’s reaction to compared with unedited cells, which did. Takahashi and Yamanaka’s 2006 Commenting on his team’s findings, DOLLY’S BIRTH 276 PREVIOUS ATTEMPTS breakthrough? “I was very excited, 276 Dr Tilo Kunath said: “We know that and still am. I believe that therapies Parkinson’s disease spreads from neuron- derived from stem cells will provide 2006 he became Founding Director, neuron, invading healthy cells. This could revolutionary, new treatments to MRC Centre for Regenerative Medicine essentially put a shelf life on the potential degenerative diseases, which, at (CRM), University of Edinburgh until of cell replacement therapy. Our exciting present, have no treatment. his retirement in 2012. However, he discovery has the potential to considerably “On first consideration, many people retains an active interest in ongoing improve these emerging treatments.” judge that this will be through the research at the CRM. provision of cells to replace those that On World Parkinson’s Day, 11 April 2018, Stepping forwards have died or ceased to function normally Sir Ian disclosed that he had been Prof Sir Ian Wilmut’s curriculum vitae, he because of the disease. However, to many diagnosed with Parkinson’s disease (PD). reflects, “illustrates the equally profound of us this seems unlikely because cell The announcement coincided with the effects of happenstance and serendipity therapy depends upon overcoming so launch of the Dundee-Edinburgh …” But notwithstanding its serendipitous many challenges.” Parkinson’s Research Initiative to nature, Frostie, Tracy, Morag, Megan and, These challenges include those of investigate causes of the disease and of course, Dolly, have etched Wilmut’s further defining the immunogenicity translate discoveries into new therapies. name in the annals of biology, and of iPSCs to enable better evaluation Supporting the initiative, Wilmut said he current progress in stem cell research of innate and host immune responses would be “happy to act as a guinea pig shows that his influential contributions and the establishment of standardised and either donate tissue or try new continue to make an impact. protocols for iPSC generation and treatments”, adding: “Initiatives of this It is perhaps fitting to quote from the differentiation. kind are very effective not only because final paragraph of hisAfter Dolly: The Uses they bring more people together, but and Misuses of Human Cloning (2006). “I want New challenges because they will include people with to be able to change my destiny rather From 2000 to 2005 Wilmut was the different experience and expertise. It was than be condemned to a particular fate… Roslin Institute’s Head of Department, from such a rich seedbed that Dolly For me, the widespread use of genetic Gene Expression and Development; from developed, and we can hope for similar and reproductive technologies is not a 2005 to 2006, Professor of Reproductive benefits in this project.” step backwards into darkness, but a step Science, University of Edinburgh; and in Meanwhile, progress continues apace. forwards into the light.”