Epigenetic programming of sex determination in A. freiburgensis

In a plethora of organisms, environmental cues sensed by the maternal neuronal system are involved in the transmission of selected characteristics to the following generation. This concept falls within the study of "epigenetics" and challenges the dogma that information cannot pass from the somatic cells to the germline. The study of the "Dutch Hunger" is a notable example showing how malnutrition of pregnant women during World War II led upon an increased incidence of metabolic diseases in the offspring, such as diabetes and obesity. In addition, offspring of female domesticated animals that were exposed to a high fat (16%) and high sugar (33%) diet had a higher rate of developing metabolic disorders, such as impairment in glucose homeostasis and locomotor activity, increased fat deposition and hypertension.
In the case of the nematode Auanema freiburgensis, resistance to stress and the sex ratio, also depend on sudden environmental changes experienced by the mother. When the population rises within the species, the mother can sense the environmental change using olfactory neurons and subsequently produce stress-resistant progeny (dauers), which can adapt to the forthcoming lack of nutrients. These dauers resume development once found in a less crowded environment and become hermaphrodites, which have the ability to self-fertilise.
In previous work, candidate chemicals sensed by the mother's olfactory neurons were found. Moreover, former research demonstrated that changes in the germline transcriptional profile were also induced upon exposure to the crowding chemical. The current project will determine more aspects involved in the mechanism of transgenerational inheritance. It will be focused on deciphering how the environmental stimulus is recognised by the mother and transferred to the gonads.