Transgenerational epigenetic inheritance increases trait variation but is not adaptive

Area of Science:

• Ecology
• Evolutionary Biology
• Genetics

Background:

• Organismal responses to environmental change are crucial for biodiversity conservation.
• Epigenetic modifications, including those inherited across generations, are increasingly recognized for their role in environmental stress responses.
• The extent and fitness impact of epigenetic marks beyond maternal inheritance remain largely unexplored.

Purpose of the Study:

• To investigate how transgenerational epigenetic inheritance (TEI) influences the phenotypic response of Daphnia clones to the environmental stressor Microcystis.
• To quantify the fitness consequences of TEI in offspring across generations.

Main Methods:

• Eight Daphnia genotypes were subjected to Microcystis exposure or control treatments (P0 generation).
• The fitness (survival, growth, reproduction) of descendants was tracked up to the F3 generation.
• Phenotypic trait variance was analyzed in relation to TEI.

Main Results:

• Transgenerational epigenetic exposure to Microcystis resulted in decreased survival and growth rates in offspring.
• No consistent effects of TEI were observed on offspring production.
• TEI was linked to increased trait variance, suggesting a potential for heritable bet-hedging strategies.

Conclusions:

• TEI can induce significant phenotypic shifts in response to environmental stressors like Microcystis.
• These shifts, however, were not consistently adaptive, indicating transgenerational adaptive plasticity may be infrequent.
• TEI influences organismal responses to environmental change, but its adaptive significance requires further investigation.