Ruiting obtained his PhD from university of Sydney and is currently Professor at UNSW.
Professor Lan came from a population genetics background and lectured in genetics before doing his PhD in molecular genetics. He combined the two fields in his research on bacterial population structures and evolution of pathogens, making unique contributions to this research field. He has made major advances in the studying of enteric pathogens and evolution of bacterial clones. Ruiting initiated the use of genomic subtraction to study genome variation before the genome sequencing era and discovered that horizontal gene transfer is a major factor in bacterial evolution. Although that observation was met with scepticism at the time, the findings have now been confirmed by genome sequence data. Based on that study and genome data he proposed the species genome concept which has been widely cited, and the proposal has been vindicated by microarray studies and rapidly accumulating intraspecies genome data.