Each characteristic is encoded by a pair of chromosomes. How does our body decide which of the DNA molecules to transcribe into RNA?
In: Biology
Feedback is the phenomenon that allows complex, potentially Turing complete behavior to arise from a system. It is achieved when the output of a system acts as an input and changes the new outputs.
The DNA produces RNA, the RNA moves to the ribosomes and creates proteins. Some proteins (histones and neucleosomes) act as spools and wind up sections of DNA, keeping them protected and temporarily unable to be used. Some proteins (helicases) cause sections of.the DNA to unzip, preparing them for transcription. There are plenty of other interactions as well.
The DNA ultimately produces the proteins. And the proteins ultimately control what the DNA does. And thus we have feedback. And from feedback we can get complex behavior.
There are a whole bunch of signaling pathways that ultimately let the cell ‘know’ which parts of the DNA should be transcribed and when. The chromosomes are normally folded up tight, around proteins called histones. These and other proteins can be in the way enough that genes can’t be transcribed, but they can be moved out of the way. There are other proteins or RNA molecules that can bind to the DNA, that can either block some genes, or cause others to be transcribed more. The DNA itself can be modified in ways that determine if it can be transcribed
We do not quite know. This is obviously a set of complex signaling pathways. Quite a number of researchers are trying to figure out how this all works but it is probably going to take quite a long time to figure it all out, and we have just started.
What we have found out is that the parts of the DNA which is not encoding proteins do have an impact on how this process takes place. It can look like there is a set of DNA which catches specific proteins and when the conditions are right this starts the process to copy the DNA into RNA. Similar structures triggers the RNA to be copied into proteins and finally another sequence at the end of the RNA changes what happens to the protein once it is made and also how many proteins should be made from this RNA.
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