While there isn't as much information about their origin as with other species, Star Trek provided several interesting details over the years. The Borg come from the Delta quadrant, and it took them thousands of years to evolve into a life form that combined organic matter with technological implements.
While they originated from the Delta Quadrant, the actual history of the species known as the Borg was quite spotty in Star Trek canon. During the events of 1996's Star Trek: First Contact the Borg Queen mentioned that the species started as normal sentient life but had eventually adapted using cybernetic technology.
The letter writer, Christopher Haviland, also speculated that the original Borg drones were members of a race called "the Preservers", which Spock had suggested in the original series episode "The Paradise Syndrome" might be the reason why so many humanoids populate the galaxy.
The Borg Homeworld is Earth. That is why the Borg have such a hardon for Earth that they put resources into capturing Earth on the other side of the galaxy and assimilating humanity rather than continuing their geometric expansion out from the Delta Quadrant.
Although any further details would be purely speculative, it fits with the established canon and timeline that the ancient Romulans could've started experimenting with artificial life forms, accidentally created the Borg and realized the terror their experiments had given rise to.
Could "Q" or a "Founder" be assimilated by the Borg? Yeah, maybe. There seem to be some species like species 8472 though, that are just incompatible with assimilation, but for the most part they can usually find a way to assimilate many species.
The Borg queen was a member of Species 125. Note: This is NOT a PC and NPC rated species. Species 125 is the Borg designation for a species as yet unknown to the Federation outside of the Collective. However, it is likely that this species has been completely assimilated.
The episode first aired in broadcast syndication on May 5, 1989. It was written by executive producer Maurice Hurley and directed by Rob Bowman. "Q Who" marked the first appearance of the Borg, who were designed by Hurley and originally intended to appear in the first season episode "The Neutral Zone".
The borg collective as a whole didn't join the federation it was just a small splinter group of the borg that joined the federation the main borg collective is still an enemy of the federation and would mostly likely never join the federation instead would keep on trying to assimilate the federation.
The Borg discover Species 8472 in the Delta Quadrant and try to assimilate its biotechnology, which is more advanced than anything the Borg have seen. The Borg quickly realize that Species 8472 is immune to assimilation and that contemporary Borg technology is no match for it.
Zero (Angus Imrie) merged his mind with the Borg Collective, but his attempt to ask for a solution about the Living Construct fell on dead ears. Instead, the Borg quickly assimilated Zero.
Guinan is an El-Aurian, a race of empathic and telepathic beings who are extremely long-lived; Guinan's exact age is never mentioned, but she is well over 500 years old by the time of her appearance in Star Trek: Picard season 2.
Whilst the Borg are primarily a nomadic space-bearing race they do however occupy planets with a typical population of nine billion drones primarily for the purposes of strip-mining the planets of all natural resources.
Thankfully, the worst case scenario was avoided, and the original Borg are now extinct, removing them as a future threat to Captain Michael Burnham (Sonequa Martin-Green) and the crew of the USS Discovery.
Q is a fictional character, as well as the name of a race, in Star Trek, appearing in the Next Generation, Deep Space Nine, Voyager, Lower Decks, and Picard series and in related media. The most familiar Q is portrayed by John de Lancie.
Q throws the Enterprise into uncharted space where it encounters and is engaged by a dangerous alien vessel of a previously unknown species: the Borg. When the vessel instantly and effortlessly overwhelms the Enterprise, Picard realizes that the Federation may not be as ready for the future as he thought.
Assimilation. The Borg don't reproduce but assimilate other humanoids, which keeps their population rejuvenated. Assimilation can be traced back to the exact beginning of the Borg. When a Borg drone assimilates another humanoid, they use tubules to inject exactly 10,000 nanoprobes into a victim's blood stream.
Only one Queen exists at any given time; when she is destroyed, a new Queen takes her place. In Star Trek: Voyager, it's revealed that the Borg Queen isn't a singular entity, but the name given to any that serves as its host, possessing all previous Queen's collective consciousness.
Seven arrives at the Artifact, a disabled Borg cube captured by the Romulans, after being summoned by Picard's companion Elnor. To save the former Borg onboard from execution at the hands of the Romulans, she temporarily connects herself to the cube inside the queencell, taking on the role of a Borg Queen.
Originally Answered: Is the Borg Queen 7 of 9's mother? We know for a fact that she is not. The Queen was a member of Species 125, Erin Hansen was human and therefore a member of Species 5618.
Species 8472: Also known as the Undine, they were a highly advanced and biologically unique species from fluidic space. Due to their vastly different biology, the Borg were unable to assimilate or adapt to them.
As far as I know, the "Bad Borg" hail from the Delta Quadrant, and though we don't know just how old that collective is, it is ancient. The "Good Borg", Jurati's Borg, were established in the Alpha Quadrant in the 21st century, when the queen from the alternate timeline and Jurati merged.
However, a Hirogen can be seen during mind meld scenes in "Infinite Regress", indicating that Seven of Nine herself, or at least the Borg as a species, already had assimilated Hirogen before Seven's liberation from the Collective.
