Simen studies how genomes evolve and how genomic variation is linked to adaptation, with particular focus on novel variation from whole genome duplications. He is taxonomically promiscuous, having worked on mosquitoes, wheat (Science 2014 a b c) and salmon (Nature 2016).
In his PhD, Simen studied the genetic mechanisms and evolution of freezing tolerance in grasses. He has worked in the International Wheat Genome Sequencing Consortium and the International Consortium to Sequence the Atlantic salmon Genome, contributing key insights into how wheat evolved, how hybrid genomes subdivide molecular roles among themselves, and how whole genome duplication in vertebrates drive evolutionary innovation – the raw material for adaptation. He currently leads the GenoSysFat project, funded by a TOPPFORSK grant for talented young researchers from the Norwegian Research Council.