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This past June, Princeton University molecular geneticist Coleen Murphy and colleagues published their research documenting that after consuming a pathogen, C. elegans can pass on information about it to their offspring, allowing the next generation to avoid making the same mistake. But only some pathogenic bacteria trigger this transgenerational avoidance response. Murphy wanted to know why.
Her group started exposing worms to various bits of pathogenic Pseudomonas bacteria, which the team had previously found to trigger the avoidance response across generations. To the researchers’ surprise, exposure to bacterial metabolites did not trigger an avoidance response, nor did bacterial DNA. Small RNAs in the bacteria, however, did. When they squirted a bunch of Pseudomonas small RNAs onto the worms’ usual diet of E. coli, the nematodes later avoided eating Pseudomonas, even though they’d never encountered the actual organism before.
The team looked for differences in the expression ...
