Hurst works on fundamental problems in the evolution of genetic systems, such as understanding why some sorts of mutations are less damaging than predicted whilst others are more damaging. Mutations that change proteins are, surprisingly, often not especially deleterious. Hurst showed that this was because the genetic code is structured in a way that renders it highly error-proof. Similarly, in applying network representations of gene interactions, he revealed why many deletions of genes have little effect and which deletions tend not to be recessive.[24]
By contrast, Hurst revealed that genomic changes often considered to be relatively harmless – such as gene order changes and mutations at 'silent' sites – are under selection for unanticipated reasons. He also showed how synonymous mutations can disrupt the way gene transcripts are processed. Similarly, in showing that genomes are arranged into gene expression domains, Hurst revealed that genes can affect the expression of other genes in their vicinity. As of 2015[update] translation of this fundamental work to medicine is a focus of his research.[24]
Hurst is a leading authority on evolution of genetic systems. He showed that the genetic code is adapted to minimise errors, synonymous mutations in mammals are under selection and gene order is non-random. He was first to recognise the impact of gene expression levels on protein evolution. Hurst spearheaded novel approaches to evolutionary genetics deriving fitness from underlying biochemistry to predict the outcome of laboratory models. This led to fundamental insights into causes of gene dispensability, dominance and variation in gene family size. Hurst, collaborating with cell biologists, identified the human-specific pluripotency gene network and discovered human naïve stem cells.[25]
^ ab"Archived copy"(PDF). Archived from the original(PDF) on 17 September 2012. Retrieved 15 June 2011.{{cite web}}: CS1 maint: archived copy as title (link) Zoological Society of London Scientific Medal Winners
^Lercher, M.J.; Urrutia, A.O.; Hurst, L.D. (2002). "Clustering of housekeeping genes provides a unified model of gene order in the human genome". Nature Genetics. 31 (2): 180–183. doi:10.1038/ng887. PMID11992122. S2CID5797987.