Fig. 6

Environmental conditions affect piRNA biogenesis and fitness intergenerationally in C. elegans. PiRNA biogenesis is reduced at 25 °C compared to 20 °C leading to an increase of piRNA targeted genes. The increase of expression of certain genes observed in parental animals grown at 25 °C and resulting from the loss of piRNAs is maintained in the progeny even if grown at 20 °C. Descendants of animals grown at 25 °C display a decrease in fitness at 20 °C compared to descendants of animals grown at 20 °C or animals grown at 25 °C on pathogenic bacteria