From what I have read, core Gnome development began with C and this was extended by Vala (2006) and Genie (2008). Vala syntax appears to have been aimed at the Java/C# syntax/developer, whereas Genie appears to be aimed at Python (and a handful of others).
There are also certain developers who appear to be attempting to scuttle these two great development tools - by pushing for a move to, for lack of a better term, non-native technologies like Javascript and Rust - requiring additional virtual machines or runtime binaries.
Yet there appears to be a resurgence in Vala primarily driven by the applications developers. This is clear from the rise in activity on the Vala compiler and the proposed activities of the 2018 Outreach Program where Vala is a core feature.
So this brings us to the technical relationship to Genie. From my reading, Genie only depends upon GLib whereas Vala depends upon the Gnome desktop environment. Is this relationship correct? Secondly, is Genie built into the Vala compiler valac
or is it separate? From a compilation perspective, are they integrated technologies?
Although both Vala and Genie are being developed and promoted by GNOME, programs developed in Genie don't depend on the GNOME Desktop Environment, usually requiring only GLib.
That statement is incorrect, I believe, as you have confirmed. – Proven