Cathal studied theoretical physics (BSc) and molecular evolution/bioinformatics (PhD) in Trinity College Dublin. Following a short postdoc at the Royal College of Surgeons he took up a position as director of training at the South African National Bioinformatics Institute (SANBI). He became a senior lecturer in bioinformatics at SANBI, and subsequently associate professor and director of the computational biology group at the University of Cape Town in 2004. In 2009 he joined NUI Galway as Stokes Professor of Bioinformatics. Research interests include sources and consequences of variation in genomics data as well as the development of methods to analyze high throughput data from heterogeneous samples. His research group also has interests in diverse areas of molecular evolution from probabilistic modeling of viral sequence evolution to evolutionary aspects of gene expression regulation and mRNA splicing.