[DIYbio] Re: Random gene?

Your question is interesting but not quite clear could you be more specific? What do you mean by pick one of the genes at random?
If a transcription factor is always picking one of the genes at random then the cell will not produce only one pigment, which I think is what you are after?
If you want each cell to randomly activate one and only one of the genes this becomes much more difficult.

Understand that _nothing_ in biology is _random_ what this means is that choosing your gene needs to be regulated by _something_. Temperature, light, pressure, amount of a transcription factor.

Next, once a genetic change is made, say by using Lox/Cre or CRISPR, there is no going back(or it is very very complicated) so the "randomness" would only be good for one generation. i.e. you transform a bacteria with the original plasmid and it will randomly be a color but each generation after that will be the same color.

However, if that is all you want then the simplest approach would probably best be done by creating a library of plasmids with promoters that allows a constitutively active transcription factor to activate only one of the genes at a time in the cell. Then transforming your bacteria with all of them and each will contain a random gene that they activate for one generation or maybe multiples to create different combinations of pigments.