J. Mark Cock obtained his PhD from Leeds University in 1985 (UK) and worked for several years on nitrogen metabolism and nodulation in terrestrial plants in post-doctoral positions at the University of Florida (Gainsville, FL), at the University of Warwick (UK) and at the CNRS-INRA laboratory in Castanet, Toulouse (France). From 1992 to 2002 he led a group working on the molecular basis of cell-cell recognition during the self- incompatibility response in Brassica and on petal development at the Ecole Normale Supérieure de Lyon (France). In 2002, he moved to the Station Biologique de Roscoff (France) where he initiated a project aimed at developing the filamentous brown alga Ectocarpus as a genetic model species for the phaeophyceae in order to study developmental processes in this phylogenetic group. This project included the sequencing and analysis of the 214 Mbp Ectocarpus genome, the first sequenced macroalgal genome. This work was carried out in collaboration with Genoscope and the VIB in Ghent and involved the coordination of a large international consortium. The Roscoff group is currently investigating genetic control of developmental processes in Ectocarpus, in particular life cycle regulation, using genetic and genomic approaches. Major recent advances include the cloning of the first brown algal developmental genes by forward genetics, the development of CRISPR-Cas9 gene knock-out methodology for Ectocarpus, the first analysis of chromatin modification dynamics in a macroalga, the identification of master regulators of the Ectocarpus life cycle and the description of brown algal sex chromosomes. Mark Cock is currently coordinating a large-scale project that will generate complete genome sequences for 45 species of brown algae plus four sister species (https://phaeoexplorer.sb-roscoff.fr/home/).