Danger avoidance can be genetically encoded 

An organism’s phenotype can change during its lifetime due to epigenetic mechanisms. For example, in the microscopic roundworm Caenorhabditis elegans, starvation or heat stress prompts animals to adapt to these conditions by varying the expression of multiple genes. At the level of the genome, these changes can be made durable by altering how tightly the DNA that encodes a gene is packed, thereby regulating its accessibility to RNA transcription machinery. Alternatively, cells can engage mechanisms that destroy or sequester protein-coding RNA transcripts. When these modifications are made in germ cells, they can be passed down to future generations in a phenomenon is known as transgenerational epigenetic inheritance. Studies have shown that C. elegans adaptations to starvation and heat stress can be inherited for several generations. Might more complex phenotypes, such as behavioral changes, also be passed down in this way?

“In their natural environment, worms come into contact with many different bacterial species. Some of these are nutritious food sources, while others will infect and kill them,” said Murphy, a professor in Princeton’s Department of Molecular Biology and the Lewis-Sigler Institute for Integrative Genomics. “Worms are initially attracted to the pathogen Pseudomonas aeruginosa, but upon infection, they learn to avoid it. Otherwise they will die within a few days.”

Moore and her colleagues investigated whether C. elegans can convey this learned avoidance behavior to their progeny. They found that when mother worms learned to avoid pathogenic P. aeruginosa, their progeny also knew to avoid the bacteria. The natural attraction of offspring to Pseudomonas was overridden even though they had never previously encountered the pathogen. Remarkably, this inherited aversive behavior lasted for four generations, but in the fifth generation the worms were once again attracted to Pseudomonas. In another surprise, the researchers observed that inheritance of learned avoidance was not universal for all pathogenic bacteria; although mother worms could learn to avoid the pathogenic bacterium Serratia marcescens, which is less abundant than Pseudomonas in C. elegans’ environment, this aversion was not passed down to offspring. Intrigued, the researchers set out to explore what controls transmission of P. aeruginosa avoidance behavior across generations.

Source: Danger avoidance can be genetically encoded for four generations, say Princeton biologists