Andrew Jackson is a clinical geneticist who has applied his medical background to running a highly successful research group in the MRC Human Genetics Unit, University of Edinburgh at the Western General Hospital. Andrew has specialised in the molecular characterisation of human genetic diseases associated with DNA replication mediated mutation. In particular he has pioneered research into diseases such as Aicardi-Goutieres and Meier-Gorlin syndromes. This has led him to the characterisation of nucleases that promote and repair DNA replication processes. In particular he has studied ribonuclease H which removes misincorporated ribonucleotides from DNA. In effect he uses known human genetic disease as a way to determine fundamental aspects of nucleic acid biology.