Different states of eDNA
Environmental DNA can be present in four principal states described in
Figure 1. Here we focus on eukaryotic extra-organismal
eDNA9,
which is commonly analysed to make accurate inferences as to whether or
not a targeted species (usually of conservation or management concern)
or community was present at time of
sampling16.
Additionally, we focus on eDNA states at the cellular level and below
because all eukaryotic life forms have cells as a basic unit
encapsulating DNA. We recognize that extra-organismal eDNA may also
originate from even more complex structures such as tissues and gametes,
but variations in these structures are complex across eukaryotes and
beyond the scope of what we address in this perspective. However, this
variation in tissues and other structures is likely a main factor that
contributes to species-specific rates of DNA degradation and
persistence.