Antony John Clark OBE, FRSE This obituary first appeared in The Guardian on 25 August 2004 http://www.guardian.co.uk/science/2004/aug/25/obituaries.health The sudden death of Professor John Clark, at the age of 52, has robbed Britain of a world leader in animal science and biotechnology, and an individual whose commitment to science was based on a genuine concern for others. A visionary, energetic and resolute leader, he made outstanding contributions not only in research, but also in translating it to the commercial environment. Clark was director of the Roslin Institute, near Edinburgh, one of the world's leading centres for research on farm and other animals, funded by the Biotechnology and Biological Science Council. He pioneered the development of techniques for the genetic modification of livestock that led to the cloning techniques and the birth, in 1996, of Dolly the sheep, the first animal to be cloned from an adult cell. This event created entirely new opportunities in research and regenerative medicine. Appointed to the then Animal Breeding Research Organisation in 1985, Clark soon assumed leadership of a project to produce human proteins in the milk of sheep. Its success required an understanding of the mechanisms that regulate the functioning of genes, the technical ability to manipulate DNA sequences and methods for the introduction of gene sequences into sheep embryos. While these are now commonplace, this was not the case at the time, and the project was technically challenging. The birth, in 1990, of Tracy, the first sheep to produce very large quantities of human protein in her milk - alpha-1-antitrypsin for the treatment of cystic fibrosis - was a milestone in the field, and a success that laid the foundation for the continuing reputation of the Roslin Institute (as it became in 1993) as pioneers in transgenic technology. The development of cloning techniques at Roslin in the mid-1990s provided the first opportunity to introduce precise genetic changes in animals other than mice, and Clark and his colleagues were the first to produce a large animal from which a specific gene had been removed (a prion protein gene from a sheep). Characteristically quick to recognise scientific opportunities, Clark responded to the news, in 1997, of the isolation of the first human embryonic stem cells by rapidly establishing his own projects building on that research. Currently, the laboratory he managed is working on the derivation of liver cells and neurones from human embryonic stem cells for potential use in the testing of new drugs and the treatment of Parkinson's disease, stroke and spinal cord injury. Scientists in the UK are often criticised for failing to convert scientific advances into practical benefit. Clark was an exception in that he had a clear commitment to commercialising research - and the entrepreneurial flair to achieve this. The successful project to produce human proteins in sheep milk was carried out at Roslin, but provided the intellectual basis for the establishment of PPL Therapeutics in 1987. Clark's experience with the creation of that company was invaluable when Dolly followed. The establishment of another company, Roslin BioMed, and its subsequent acquisition by the US Geron Corporation in 1999, delivered a six-year commitment to fund human stem cell research at the institute, and has underpinned its status as a leader in this exciting new field. Most of Clark's career was driven by setting a strategy in which possible applications provided the rationale and justification for research. Thus, he was ideally suited to provide the scientific leadership and direction when he became director of Roslin on August 1 2003. Irrespective of the level at which he was operating, from team leader to director, he always ensured he had time for his staff, especially for the many students he personally supervised. Clark was born in Blackpool, but the family moved to Lincolnshire, where he was educated at Barton grammar school. After he graduated in natural sciences at Christ's College, Cambridge, in 1973, he and his wife Helen began what they later called their "world tour". First, they went to the University of Western Ontario, Canada, where Clark obtained an MSc for studies on the regulation of development in a mudsnail. They then travelled for a year through the US and South America. This experience had a lasting impact on Clark, and he could always amaze with anecdotes of their many adventures, such as horseback journeys to visit remote archaeological sites in the Colombian rainforest. Back in Britain, Clark began research in what were still the very early days of molecular biology. Working in Edinburgh, he completed a pioneering study on human satellite DNA, for which he was awarded a PhD in 1982, before working, with John Bishop, of the Institute of Genetics at Edinburgh University, on genes that function in the liver of mice Clark was awarded the OBE in 1997, elected a fellow of the Royal Society of Edinburgh in 1999, and was a valued contributor to numerous scientific committees and working groups. A widely read man, he enjoyed music, dancing and a broad circle of friends. Though he, Helen and his two sons, Charlie and Laurie, travelled widely together, they returned repeatedly to the tranquillity of Colonsay, in the Inner Hebrides. Ian Wilmut Anthony John Clark, MA, MSc, PhD, scientist and entrepreneur, born September 18 1951. Elected FRSE March 1999. Died August 12 2004.