Re: Article: On Noise in Gene Expression


"Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx> wrote
> Four potential sources
> of variation in gene expression must be considered: (i) as described
> above,
> the inherent stochasticity of biochemical processes that are dependent on
> infrequent molecular events involving small numbers of molecules; (ii)
> variation in gene expression owing to differences in the internal states
> of
> a population of cells, either from predictable processes such as cell
> cycle
> progression or from a random process such as partitioning of mitochondria
> during cell division; (iii) subtle environmental differences, such as
> morphogen gradients in multicellular development; and (iv) ongoing genetic
> mutation, either random or directed. The authors use the term "noise" in
> gene expression to refer to the measured level of variation in gene
> expression among cells, regardless of source, within a supposedly
> identical
> population.
>
I did some work on microarray data last year.
A microarray consists of thousands of dots of DNA which measure the level of
complementary DNA, which you create from RNA in your sample. Thus it
provides a measure of the level of mRNA in the cell, and thus (presumably)
gene expression.

In fact the datasets are very difficult to work with. For instance I found a
set of four genes (out of 2000) which provided a very statistically
significant discrimination between tumour and non-tumour samples, but no
sort of rhyme or reason or real biological plausibility.



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