newbie question about DNA and cells

Jayakumar, R R.Jayakumar at
Wed Dec 31 15:56:20 EST 2003

Even though all cells contain the same set of genes (genes are pieces of DNA which expresses RNA which translates into proteins), not all genes are expressed in all cells.  Through a complicated system of gene regulatory elements very early in the cell differentiation pathway, cells get specialised and channelled into particular duties.  Hence only particular genes necessary for the specific function of each cell type (which comprises a specialized tissue like the muscle or tonail) are turned on in that cell while the other genes are more or less silent or silenced.  
     If you need to know more about that, you have years of molecular biology to learn.  ACtually most of molecular biology and cell biology deals exactly with what you just asked. :-)))  If everybody knew exactly how cells function, we wouldn't have cancer or a host of other medical diseases anymore.  But we are working towards it. :-))
    bye and take care

> ----------
> From: 	owner-cellbiol at on behalf of Eric Hanson
> Sent: 	December 31, 2003 10:13 AM
> To: 	cellbiol at
> Subject: 	newbie question about DNA and cells
> Hello,
> I'm a computer scientist interested in genetics and cellular biology. 
> I have a decent understanding of the process of DNA getting converted
> to RNA, from there to enzymes, but have a question.
> Each cell has the same DNA as its base, and yet one cell might become
> a piece of tooth enamel and one might become a piece of toenail.  If
> they each have the same DNA, how does the cell know what to become?
> Thanks,
> Eric

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