Biomarkers and brains: situating dementia in the laboratory and in the memory clinic.

This paper provides a comparison of how genetic biomarkers are used (or not) in three contexts: clinic-based diagnostic work with people; lab-based research on mice and their marbles; and lab-based research on thrashing nematodes. For all the worldwide drive to find biomarkers that can be used in the detection of early, presymptomatic dementia, there is little research on how or when the association between biomarkers and a definitive disease are being made to "hold." First, we show the disjuncture between the animal modeling that underpins laboratory attempts to stabilize genetic biomarkers and the paradigms that inform clinical diagnosis. Secondly, we develop this theme to show how in our third site, an epigenetics "worm" laboratory, neurodegenerative changes are explored as located in specific gene-environment interactions over time. We speculate whether such an enactment brings us closer to a notion of "situated biology," to undercut possibilities of making genetic biomarkers of preclinical dementia hold.