Much of soil life is known only from DNA traces left in the environment. These dark taxa may be uncultured, microscopic, poorly classified, or lacking a formal name, but they are not noise. They are real branches of the tree of life that shape soils, food webs, and ecosystem processes.
Environmental DNA has transformed biodiversity research, but many surveys rely on short barcode fragments. These fragments are powerful for recognizing familiar organisms, yet they often do not contain enough evolutionary signal to place deeply novel lineages with confidence.
When a soil sequence has no close match in a reference database, it may be reported only as "unidentified eukaryote" or "unidentified fungus". Across thousands of samples, that creates a blind spot: the least-known organisms become the easiest to overlook.
Soil contains DNA traces from fungi, protists, animals, plants, and other eukaryotes.
GloSED amplifies a broad eukaryotic barcode region instead of targeting only one familiar group.
Long, high-quality reads retain more evolutionary signal than short barcode fragments.
Each OTU is linked to taxonomy, sequence data, sample metadata, and, for fungal dark taxa, UNITE Species Hypotheses where available.
GloSED was built to keep soil dark taxa in the analysis. It combines standardized global sampling with long-read sequencing and expert-curated taxonomy, so unknown organisms can still be compared, mapped, and studied.
The same primer system targets a broad range of soil eukaryotes, including fungi, protists, animals, and plants. This lets GloSED study soil communities as connected ecosystems rather than isolated kingdoms.
PacBio HiFi reads recover long ribosomal DNA barcodes spanning full-length ITS and 18S-V9 regions. More sequence information helps separate close relatives and place unfamiliar lineages more confidently.
Specialist curation with EUKARYOME and UNITE Species Hypotheses turns anonymous DNA clusters into traceable biodiversity records. Even taxa without Latin names can receive stable identifiers and be compared across studies.
GloSED contains nearly one million eukaryotic OTUs from 4,063 sites in 121 countries, including fungi, protists, animals, and plants. It captures groups that are often missed or poorly resolved in narrower surveys.
Dark taxa include decomposers, parasites, predators, symbionts, and primary producers. Bringing them into the dataset improves how we study carbon cycling, soil health, food webs, and global biodiversity change.
Nilsson RH, Ryberg M, Wurzbacher C, Tedersoo L, Anslan S, Põlme S, Spirin V, Mikryukov V, Svantesson S, Hartmann M, Lennartsdotter C, Belford P, Khomich M, Retter A, Corcoll N, Martinez DG, Jansson T, Ghobad-Nejhad M, Vu D, Sanchez-Garcia M, Kristiansson E, Abarenkov K. 2023.
Tedersoo L, Moghadam MSH, Panksep K, Prins V, Anslan S, Mikryukov V, Bahram M, Abarenkov K, Kõljalg U, Esmaeilzadeh-Salestani K, Pawłowska J, Wurzbacher C, Ding Y, Alkahtani SH, Nilsson RH. 2025.
