Populations of a species differ from place to place. I study how these differences originate, how they are maintained and how they may eventually lead to speciation. This is done by contrasting neutral genetic variation with variation that is influenced by natural selection. Admixture zones are my particular interest. At present I focus on bivalves (Macoma spp. and Scrobicularia plana) and worms (Arenicola spp. and Scoloplos armiger). The techniques I use are DNA sequencing and AFLP.
‘I try to understand historical and present-day population processes by studying DNA. Signatures that such processes leave can be detected from DNA variability, for example: colonisation, sudden population expansion, ongoing migration and selection. During my PhD work at NIOZ and Rijksuniversity Groningen (2003, cum laude) I first started contrasting selectively neutral variation with non-neutral variation. This involved breeding bivalves for estimating genetic variance for quantitative characters. I also proposed a historical scenario for populations of the bivalve Macoma balthica based on coalescent similations. As a post-doc at the University of Amsterdam I examined variation in recognition proteins of aquatic plants for understanding selective forces operating during sexual reproduction. The wish for the combined analysis of selection, history and migration led to a post-doc at Tjärnö Marine Biological Laboratories in Sweden, and to my current position back at NIOZ.’