Demonstrations of Transgenerational Epigenetic Inheritance in Various Model Systems

Transgenerational Epigenetic Inheritance (TEI) refers to the transmission of phenotypic traits across multiple generations through epigenetic mechanisms rather than through direct changes to the DNA sequence. These mechanisms are often shaped by environmental stimuli, adding a dynamic and responsive layer to inheritance that challenges traditional views on heredity. Despite its groundbreaking implications, TEI remains a relatively under-explored area, with many unanswered questions regarding how these epigenetic modifications are stably maintained through generations. This Collection gathers cutting-edge research and robust empirical data on TEI across various model systems, offering novel insights into this phenomenon.

TEI is increasingly recognized across various biological systems, including plants and animals. Plants have been instrumental in advancing our understanding of TEI, as their capacity for passing on heritable epigenetic marks, particularly DNA methylation patterns, is well documented. These marks can generate epialleles—alleles that exist in distinct epigenetic states that have been stable for multiple generations. Such inheritance patterns allow researchers to track changes in response to environmental stimuli and generate epigenetic recombinant inbred lines (epiRILS), offering intriguing glimpses into how epigenetic modifications may influence adaptation and evolution.

In animals, TEI has been well documented in fruit flies and nematodes. C. elegans offers an excellent model system for TEI research. Its fast reproduction cycle and large brood sizes make it ideal for observing transgenerational effects over numerous generations, providing key insights into the mechanisms ensuring the passage of epigenetic information through the germline.

Even so, many challenges still exist when studying TEI in plants and animals. Epigenetic reprogramming and the confounding variables introduced by genetic diversity, environmental complexity, and assessing germline transmission across multiple generations generally make studying TEI difficult. This Collection aims to also provide a platform to disseminate studies to meet these challenges and discuss emerging technologies and methodologies reshaping TEI research's landscape. These include tools allowing precise manipulation of epigenetic marks, which are becoming indispensable for dissecting the causality of specific modifications' heritability and influence on phenotypic outcomes.

Key questions addressed by this Collection include: 

• How are epigenetic modifications reliably transmitted through the germline? 

• How long-lasting are these transmitted traits across generations? 

• How might acquired traits impact evolutionary trajectories or improve adaptation to environmental challenges?

This Collection aims to shed light on the mechanisms underlying TEI and explore its potential evolutionary implications by presenting empirical evidence from diverse model systems. Given the rapid pace of advancements in the field, this collection is a critical resource for researchers fascinated by this intriguing mode of inheritance, fostering deeper understanding and opening new avenues for future research.