Robin Holliday obtained his Ph.D. at the University of Cambridge, England. He joined the scientific staff of the John Innes Institute, Bayfordbury, Hertford, in 1958, and there developed molecular models of genetic recombination.
In experimental work he studied recombination and repair in the fungus Ustilago maydis and was the first to isolate and characterise mutants defective in these processes in any eukaryotic organism.
He later moved to the National Institute for Medical Research at Mill Hill, London, and became head of the new Division of Genetics in 1970.
He was elected Fellow of the Royal Society of London in 1976.
He and his colleagues also studied possible mechanisms of the senescence of diploid human cells in culture, and their immortalisation. In 1975 he suggested with his student John Pugh that DNA methylation could be an important mechanism for the control of gene expression in higher organisms, and this has now become documented as a basic epigenetic mechanism in normal and also cancer cells.
In 1988 he moved to a CSIRO laboratory in Sydney, Australia, where he continued to study ageing, and his book Understanding Ageing was published in 1995. The main focus of his experimental work was the epigenetic control of gene expression by DNA methylation in CHO cells. These experiments provide direct evidence that DNA methylation is a primary cause of gene silencing in mammalian cells.