dr. MJW (Marieke) Jeuken

As a scientist and lecturer, I am particularly fascinated by genetic and evolutionary puzzles in plants, ranging from unexpected segregation patterns in populations to genetic conflicts.

My research on breeding for resistance to biotic stresses has given me expertise in identifying resistance genes in wild lettuce species that confer resistance to major diseases and pests in lettuce cultivation, including downy mildew and aphids.

Efforts to introgress resistance traits from a distantly related wild species (Lactuca saligna) into cultivated lettuce have introduced me to the fascinating challenges of interspecific hybridization, opening up further questions about gene-gene incompatibility, reproductive isolation, and speciation.

Interspecific hybridization between genetically distant species can lead to postzygotic reproductive barriers, including reduced hybrid viability and fertility, transmission ratio distortion, and hybrid seed lethality. These barriers complicate the introgression of desirable traits into crops by preventing allele fixation, maintaining residual heterozygosity, and causing epistatic drag. My current research focuses on identifying and characterizing these barriers in crop species to better understand and overcome the genetic constraints on crop breeding.

Picture: style (yellow), stigma (forked) and rows of fused anthers with pollen grains (dark pink) of a flower of lettuce