I am very new to the field who do not even know what is an ordinary biological network. I have some follow-up questions and would like to know if I can scale down:
I agree that no cell will express 15K genes at the same time. However, if I am going to measure the mRNA expression by RNA-seq/ microarray, I can easily get gene expression data for ~11000 - 15000 genes (after gentle filtering of genes that do not express in any of the samples). However, I wonder whether all of these genes will form a big connected network? In other words, whether genes/ proteins will tend to form many disconnected subnetworks, and these subnetworks are independent of each other (not even have any links/ edges)? I am talking about in reality (the ground truth biological system in mammalian based on our current best knowledge) but not based on the current reconstructed networks by various algorithms.
In either case, I wonder whether it is reasonable to just merge multiple networks generated by GeneNetWeaver? In the case of real biology is composed of multiple discrete subnetworks, I am thinking to simply concatenate, for instance, 10 networks with ~1500 genes together. On the other hand, if these subnetworks still have some dependency on each other, how are they usually connected? If they are connected through 1 or 2 key regulators, may I just artificially add some correlation between two subnetworks during the concatenation?
Indeed, the synthetic network does not need to perfectly fit the reality (e.g. not necessary 10 networks of ~1500 genes, but maybe 20 subnetworks with 200-2000 nodes), but I still want it to resemble those critical structures/organizations found in real mammalian systems.
Thanks!