nature.com
The potential of methylation signal detection in eDNA toward functional ecological monitoring
Environmental DNA (eDNA) refers to genetic material obtained directly from environmental samples, such as water, soil, and air1,2,3. Organisms continuously release eDNA into the environment, which accumulates in various forms4. eDNA may include free-floating DNA or intracellular, microbial DNA, or may originate from cellular debris shed, such as hair, feces and pollen5,6,7. Because eDNA may contain information about organisms inhabiting the environment, it has been utilized for monitoring biodiversity for nearly 20 years8. While the term eDNA may indicate a wide range of physical forms of DNA in the environment, we define eDNA as DNA derived from macrobial organisms such as fish and tetrapods in this perspective and exclude microbial DNA to clarify the scope. Also, our definition includes DNA obtained not only from environmental substrates such as water and soil but also from other biological materials found in the environment, including feces and shed tissues. We focus primarily on aquatic eDNA because most empirical meth-eDNA studies to date have been conducted in aquatic systems. While airborne and soil-derived eDNA show promise, research in these areas remains limited. Furthermore, interpreting their methylation signals may be harder because of highly heterogeneous sources of DNA (particularly, soil eDNA) and the stronger effects...
