They're just tiny Insecticons (much like the one we briefly see in ROTF), acting as USB drives, taking bits of info at a time. They were tiny and hard to notice and could do their task of copying Megatron's consciousness over to a Galvatron unit without detection; more specifically, to the truck (hence them crawling out of the grille), and when it came time to implement the robot form, that's when the unit kept turning out to resemble Megatron. I'm sure KSI would detect Megatron's consciousness if he started hacking into systems directly, so he had to do everything in the most subtle way possible. And because they were transferring his mind directly into the units, that's why Joshua was frustrated that Galvatron wouldn't turn out like Optimus - I mean, the design they want is right there on the computers. They told the unit to look like Optimus when it converted to robot mode, but it ended up doing its own thing. It's like if I told my printer to print a specific image, but all it did was reveal an image that wasn't even on my computer; an image that was already embedded in the paper. As for the "chromosomes" bit, that's just an emphasis that this was more than a transfer of his mentality into an empty shell. It's not just a coincidence it bears an uncanny resemblance to his former self.
And at the end of the day the insecticons are really just pure imagery to emphasise a point, like a lot of stuff in movies. It's not really something to get too hung up over.
While chromesomes weren't the best word, I think it's passable to say that since this is Brains who's saying it shouldn't be taken literally. I feel there's a good chance the bugs/chromosomes/whatever you wanna call them are a reference to RID Galvatron/Devil Gigatron where Gigatron uses similar devices brainwash humans and stuff. The whole premise of Megatron's head surviving is a bit shaky and this is one area IDW stepping in would be great, but if we don't question that little detail we could then assume that perhaps over the course of time Megatron altered himself to include these nanobugs/chromesomes/thingies as a failsafe to him dying.
I don't think they were actual chromosomes that's just what Brains called them, he's an idiot in the movie so I assume he just made up a name. They were just little things with Megatron's personality in them. Honestly, I'm surprised no one took the time to watch the security cameras since they were dealing with world conquering robot aliens. Essence makes no sense at all they weren't Megatron clones he just made them mindless killing machines that he controlled, they couldn't even defend themselves after he left them in the town. Essence is also a philosophy term not scientific one.
Not even getting his head/spine torn out by an axe keeps him down. You gotta appreciate a Megatron who comes back for another evil plot regardless of whatever killed him the last time.
Since the TFs are biological, can a human head be active or have some little signs of life after being decapitated. I guess another explanation to consider, considering Megatron/Galvatron has the ability to give life or program new minions, may be he created those bugs to do his bidding while in the lab.
They didn't discover Transformium then because they did not melt Megatron. It's what, the first robotic, humanoid alien discovery of the time, would they melt him!? They wanted to find out what made him tick, and so supposedly spawned all the shit you use today. Oh yes, and the Allspark, they can turn what they already made from Megatron's inside schematics to robots anyway! Basically, S7 and Hoover dam were research and classified origins of development. KSI, well they want to mass produce robots, there's no Allspark, so, lets try remote control. They melted the Transformers for metal because Joyce was interested in it and there was a shit ton, oh and also it must be able to shift? KSI looked at it, studied it, broke it apart, which is why they have the cubey Transformation, and called it Transformium.
You have to consider the fact that KSI is a private industry so they don't have all the secret research that the government (public yet secret) had in the past with Megatron. The "earth technology" they are referring to are the military tech that eventually made it into the private market. Things like memory foam was first invented by the government (NASA) and then passed on to private markets.
Until: "my master I have failed you..." No command but yours huh? Did the writers completely forget a line they wrote five secs before? One of the bucket full of plot holes in rotf.
This just made me wonder something: is it possible Megatron's consciousness still exists within the head at KSI, almost like he didn't want to fully pull all of himself into a new body if it didn't work. After all, KSI went through a couple different Galvatron prototypes.
I'd say it's still there. Imagine those Insecticons putting his mind in one unit when it gets pulled for analysis to figure out why it turned out wrong. Now they need to grab that data again, and even as subtle as they were, they'd be found out crawling around the unit under close inspection. And if they immediately started recycling it...well, that's it. Megatron's mind is gone. Plan fails and fails hard. Plus, Megatron's mind was one of KSI's primary sources to getting info on transformium. Megatron wanted them to get that info so his new body would be just right. They'd have started putting 2-and-2 together. "Hey, Galvatron looks like Megatron...and the data in Megatron's head is gone. There's something fishy going on here."
