Second site mutations partially restore Aβ G37L toxicity. A. Paralysis plots of transgenic C. elegans expressing wild type, G37L, or double mutant Aβ. Note that the transgenic worms expressing the candidate compensatory mutations all paralyze faster than worms expressing Aβ G37L. B. Paralysis plot of transgenic C. elegans expressing single compensatory mutations. None of these single site mutations confer obvious hyper-toxicity.