And I used sponges as an example of how a multicellular organism doesnÃ¢â‚¬â„¢t need to have cells that are Ã¢â‚¬Å“stuck togetherÃ¢â‚¬Â or connected by any sort of tissue.
That as not my point.
It does not necessarily require those things. It could be caused by a developmental block in a pre-existing genome.
Here's how it works, or how I've been taught in school.
A cell has activators, which are molecules that bond to the enhancer sequence on mRNA.
Certain cells in the body have different activators, which makes them produce different proteins, as different parts of DNA can have different enhancers.
These different proteins are differentiation. if the cells do not have different proteins, they are not differentiated.
So... for differentiation as I was taught in school to happen, New activators AND enhancers would have to evolve at the same time for them to happen.
A portion of DNA could become silenced or a mutation could render a codon unreadable.
I can't find anything on google on how gene silencing works exactly, and how it could be used for differentiation.
A mutation is out of the question for obvious reasons, as to cause cell differentiation.
Under the assumption that the only way for a cell to differentiate is through an entirely new enhancer sequence, then yes I suppose they would. But I would never make that assumption so this question is kind of silly.
Why would you have to assume that for it to work? Aren't enhancers useless without an activator to bind to them? And activators are just molecules floating around. If they have some other purpose that does not explain how it could mutate so that it bonds to the newly added enhancer at the same time.