Everything known about what switches what

This is not a selection. It is every gene-regulatory relationship recorded for tardigrades in this project's graph — every case where somebody has published that one gene acts on another in this animal. It fits on one screen, it is in two disconnected pieces, and two thirds of it is inference rather than experiment.

—known relationships

—genes involved

—disconnected pieces

—genes we can measure across development

shown by perturbation inferred from expression timing guessed from orthologues in other animals

Click any arrow or gene.

Why the line styles are the point

Almost every regulatory diagram in a paper draws all its arrows the same way. These three are not the same thing:

Solid — somebody perturbed it. Cucurbitacin B was added to juveniles and the timing of E74, E78, Hr3 and Hr4 shifted together. That is a result. Note even here that the drug shifted the whole cascade at once, so the individual steps inside it are not separated.

Dashed — one gene comes on before the other, in the right place. He-Sp6-9A appears in the lateral trunk ectoderm before He-Dll does. The authors call that consistent with Sp6-9 activating Dll. It is a good hypothesis with a good alibi, and nobody has knocked either down.

Dotted — it works that way in a fly. Three different Wnts are named as candidates for activating Distal-less, because that is the relationship in better-studied arthropods and all three are expressed in roughly the right place. That is a guess about a tardigrade made by looking at something else.

Hold the two numbers side by side. We can measure — genes changing across two days of tardigrade development, hour by hour, from sixty sequenced embryos. We know what ten of them do to each other. The gap between what can be measured and what is understood is the actual state of this field, and it is not visible in any single paper — each one shows the arrows it found, never the arrows nobody has.

What it would take to add one arrow

The equipment exists and is not exotic. Tardigrades take RNA interference by microinjection, and the protocol is published — animals are purged, lined up in oil, injected, and their progeny scored. CRISPR works too: one 2022 paper cut hemerythrin and Dsup cleanly, with every sequenced deletion junction joined without an indel.

So a dashed arrow becomes solid by knocking down the upstream gene and watching whether the downstream one still appears. Every dashed and dotted line on this page is an afternoon's experiment that nobody has done.

How this page was built

Generated from the project graph by tools/genome/regulatory_map.py, so it grows when the graph does. Every arrow carries the paper and the page it came from — click one.

Building it found the reason it had never existed: the graph had no way to say that one gene regulates another. Twenty-eight claims asserted it in prose, and prose is not a relation, so the question could not be put to the graph at all. A regulates edge was added on 21 September 2026, carrying a mode and an evidence grade, and the eight relationships above were read back out of those claims into it. That is why this page can exist and also why it is so short: what you are seeing is a first pass over the claims we happen to hold, not a literature review.

What the genes are doing, hour by hour Sixty single embryos, 9,069 genes, scrubbable — the measurement side of the gap above Genetics and genomics The genome, the chromosomes, condensin II and the preprint The open questions Including the ones these dashed arrows would close