The study finds that sexual lineage plays a key role in transgenerational plasticity

A new couple of articles published in the Journal of Animal Ecology showed that sexual lineage is important to how offspring receive adaptations from parents in stickleback fish. Researchers at the Bell lab studied how parents exposed to predators passed behavioral information to their offspring in different ways based on sex.

Bell’s research group is interested in how experience (nutrition) and genetic information (nature) come together to influence how animals develop and behave. Between parents and children, this can happen through transgenerational plasticity, as the parenting environment alters future generations.

Dr Jennifer Hellmann (assistant professor, University of Dayton, former postdoctoral researcher in the Bell lab) led the study, which examined how maternal versus paternal exposure to the same environmental condition can have different effects on offspring. and on future generations.

In the first article of the study, the researchers exposed mothers, fathers, or both parents to visual cues of risk of predation. The team then measured the offspring’s anti-predatory traits and brain gene expression in the offspring. Stickleback typically has paternal care, and previous research in the Bell lab has found that a father exposed to predators will change his behavior towards his offspring. However, in this study, the stickleback’s offspring were separated from their father, meaning that subsequent behavioral differences were due only to what the offspring inherited from their father through sperm.

“Originally, we thought there would be sex-specific effects,” said Alison Bell, professor of evolution, ecology and behavior and co-author of the study. “The sons would be more affected (than the daughters) by what happened to their fathers. That’s not what we found at all.”

The results of the study showed that fathers exposed to predators produced offspring more prone to risk, while mothers exposed to predators produced more anxious sons and daughters. Furthermore, the ways in which daughters and sons were affected by the same hereditary exposure were different. “If you scare a mother, those changes look different than if you scared a father,” Bell said. “Different traits are affected. The sex of the parent is important and the sex of the offspring is important.”

In the second article of the study, the researchers tested another generation to see how long these changes in brain gene expression and behavioral traits persisted. Given what the researchers had previously discovered about sex-dependent inheritance, they once again traced the sexual lineage that the grandparents were now exposed to. “We were evaluating four different groups through maternal, paternal, both or neither of the two exposed grandparents, which was an incredible amount of work, but these effects are clearly sex dependent and we wanted to understand that further,” Bell said. “How many generations will this effect persist, and how important is the source of the change in grandparents?”

Again, the researchers’ results were surprising. The findings suggested unique inheritance patterns: for example, fathers exposed to predators would impact their daughters, which would produce grandchildren who would be affected by maternal grandfather exposure. Along another line of inheritance – for example exposed from grandfather to son to grandchildren – those impacts of exposure would be different.

“So sex is where these traits come from,” Bell explained. “Fathers not only bring DNA into their sperm, they also pass information about their environment in their sperm. Both parents pass this type of environmental information and the appearance of these changes depends on sex at each stage of the process. grandfather, parent and offspring “.

This study is one of the most careful to date examining sexual lineage in transgenerational plasticity and was supported by a Postdoctoral National Research Service Award from the National Institutes of Health at Hellmann, NIH and the School of Integrative Biology.