Actually no, that IS often the case. As I mentioned previously; in order for RNA polymerase to be able to transcribe any sequence of DNA, it MUST HAVE a binding affinity to DNA that’s non-specific with respect to the nucleotide sequence. If you eliminate this non-specificity, you would have to have a unique RNA polymerase for every gene with a unique sequence. That’s obviously not the case. Initiation factors biases the affinity of the holoenzyme towards promoters or promoter-like sequenses, but it does not eliminate the non-specificity of RNA polymerase. It would be lethal if it did.
People are often saddled with the idea that the inner workings of the cell work in lock step like the gears of a clock, and any presence of noise just happens in the background that is detrimental to function and has to be corrected for. On the contrary, the stochasticity in biochemistry very often UNDERPINS function. Noise plays a role that is VITAL to life.
Noise in Biology - PMC The new generation of “biological physicists”, many of them trained in nonlinear dynamics and statistical physics, started to view fluctuations not as a nuisance that makes experiments difficult to interpret, but as a worthwhile subject of study by itself. Researchers are finding more and more evidence that noise is not always detrimental for a biological function: evolution can tune the systems so they can take advantage of natural stochastic fluctuations.
All processes in Nature are fundamentally stochastic, however this stochasticity is often negligible in the macroscopic world because of the law of large numbers. This is true for systems at equilibrium, where one can generally expect for a system with N degrees of freedom the relative magnitude of fluctuations to scale as 1/𝑁‾‾√. However, when the system is driven out of equilibrium, the central limit theorem does not always apply, and even macroscopic systems can exhibit anomalously large (“giant”) fluctuations Keizer (1987). There are many examples of this phenomenon in physics of glassy systems, granular packings, active colloids, etc. Biology deals with living systems that are manifestly non-equilibrium, and so it is not surprising that noise plays a pivotal role in many biological processes.
No, I fully understand the point you are trying to make. However, your argument wholly omits the reality of non-specific binding. While you acknowledge this happens, you dismiss it’s importance and refuse to see how this makes the reasoning that binding is an indication of function highly specious… EVEN when your very own citation spells this out in the very next paragraph following the one that you quoted. Good grief.
Their reasoning was flawed not simply because of that. According to their reasoning, the presence of any “biochemical activity” (such as protein binding and RNA transcription EVEN if it occurred ONLY once in one cell type) is definitionally the same as “functional”.
An integrated encyclopedia of DNA elements in the human genome | Nature
The Encyclopedia of DNA Elements (ENCODE) project aims to delineate all functional elements encoded in the human genome1,2,3. Operationally, we define a functional element as a discrete genome segment that encodes a defined product (for example, protein or non-coding RNA) or displays a reproducible biochemical signature (for example, protein binding, or a specific chromatin structure).
The vast majority (80.4%) of the human genome participates in at least one biochemical RNA- and/or chromatin-associated event in at least one cell type.
In other words, any sound = signal. No room for noise under this thinking.
Wrong, that’s NOT what you have been trying to say. You have said, right in the previous comment even, that there was nothing wrong with the reasoning that the people of the ENCODE project used to assign function at the mere presence of biochemical activity (of any degree).
What WE and that particular paragraph are pointing out is an exact counter to such specious reasoning. While assays that detect biochemical activity are important (NOBODY here is saying otherwise, that’s not what we disagree on), the mere presence of binding cannot be interpreted as an indicator of function, because such biochemical activity can occur due to stochastic processes.