Re: Gene expression questions

On Feb 2, 1:19 pm, "sk8terg1rl" <sk8terg1rl_2...@xxxxxxxxxxx> wrote:
Hi group,

I was just curious if cells make assumptions as to how to translate &
express genes in a genome. For example, when turning a fertilised egg
into a living human, do the cells assume that loci I-J code for hair
colour, K-L code for physique, M-N code for intelligence and so on?

If the cells indeed make such implicit assumptions, where is the data
for these assumptions stored and how are they themselves translated?

If the cells don't make such assumptions, how does nature still
understand the contents of any genome pretty much all the time while
we struggle with understanding even one within our lifetime?

My guess is that the cells do have a set of fundamental implicit
assumptions for translating genetic data, but the clever thing about
it is that the assumptions are purely a consequence of natural laws
like concentration gradients and reaction rates.

Any citations comprehensible to someone who is not a geneticist or an
IQ of 180 would be appreciated :-). By the way, what is the pertinent
field I'm asking about? Molecular biology?

skate x

Sean Carroll has published some accessible books that deal with the
questions you're asking.
Try "Endless Forms Most Beautiful: The New Science of Evo Devo and the
Making of the Animal Kingdom" for an approach aimed at a layperson.

A brief answer to your question is: transcription factors. A
transcription factor is a molecule that allows the gene expression
machinery to be specific. Cells have a general mechanism to express
their DNA, a molecule called RNA polymerase. It copies (transcribes) a
gene so that it (the gene) can be expressed (translated). A
transcription factor confers specificity on RNA polymerase, so it
transcribes only one or a few target genes. The transcription factors
are themselves gene products, so you see that it is possible to
generate a cascade of different gene expressions in different cells,
depending on an initial starting trigger, which might be a
concentration gradient.

This is an area of molecular biology called developmental genetics or
developmental molecular genetics. You might look at some Developmental
Biology books, but most of them assume a more advanced background.

Hopes this helps.


.

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