The latest 'dev' patch includes a fairly thorough restructuring of the technology tree, along with significant changes to almost all ship hulls.
If you want a rough overview of how things are currently connected, this version of the tech chart is a more-or-less correct visualization of the in-game techs as of r13622 r14187 r16134.
You should be aware that this version of the tree includes many unimplemented techs. For example, there are now parts of the tree that anticipate the planned mining, farming, and morale mechanics, but, at the moment, you'll get no benifit from researching them. More of the tier 3 and 4 weapons are present, but, most aren't working as intended. (For example, the Stellar Surge Beam lacks the ability to destroy planets.)
This round of changes is not backwards compatible -- so, when the patch migrates to stable, all your old save games will once again fail to load.