WARM MEMORIES: Researchers engineered C. elegans with multiple copies of a transgene called mCHERRY connected to a promoter for daf-21. When kept at 25 degrees, the worms began to fluoresce red and had progeny that showed similarly elevated expression of the transgenes, despite never having experienced the higher temperature—an effect that persisted for seven generations. When worms were kept at 25 degrees for five generations, the memory of the heatwave lasted longer, with expression levels taking as many as 14 generations to return to normal.THE SCIENTIST STAFF
The paper
A. Klosin et al., “Transgenerational transmission of environmental information in C. elegans,” Science, 356:320-23, 2017.
When genomicist Ben Lehner and his colleagues at the Centre for Genomic Regulation in Barcelona engineered nematode worms to express a fluorescent reporter, they were hoping to learn about the control of gene expression. Fluorescence indicated activation of the promoter for the gene daf-21, which encodes an essential C. elegans heat-shock protein. Glowing worms meant high expression levels; dull worms, low expression. But during the project, the team stumbled across something else.
“Working with this strain, we noticed that if you had individuals that were brighter, their progeny tended to be brighter,” says Lehner. With lab worms that are genetically identical, “this is something you don’t normally see. ...
