Researches by a Princeton University-led team have observed that C. elegans can transmit complex learned avoidance behaviors from parent to progeny via eggs and sperm cells, giving the offspring an inherited mechanism for surviving dangerous conditions.
The most important set of genetic instructions that we all get comes from our DNA, conveyed through generations. The environment we live in, however, can also make genetic changes. These kind of effects on the traits of offspring without alteration of DNA sequence is known as transgenerational epigenetic inheritance (TEI). The research discovered that C. elegans that become ill from ingesting pathogenic Pseudomonas aeruginosa (known as PA14) quickly learned to avoid the bacterium and could pass down the learned behavior for four generations through the TEI process.
Neuronal sensory pathways are critical for this inherited avoidance, since avoidance behavior in both mothers and their progeny was associated with elevated expression of several neuronally-associated genes. Among these, increased expression of the TGF-beta ligand daf -7 in mothers was needed for progeny to inherit pathogen aversion. The transgenerational learned pathogenic avoidance of C. elegans was investigated to be mediated by TGF-beta and the Piwi/PRG-1 Argonaute pathway.
Interestingly, the researchers also found that inheritance of learned avoidance was not universal for all pathogenic bacteria.