🚀 go-pugleaf

Hi all,

I am a computer scientist trying to understand genetics. With this
in mind, I have the following questions.

I understand the term locus to mean the position of a gene on a chromosome.
For example, if a gene spans the 100th to the 175th base pairs of the
chromosome then its locus is 100.

I understand the term allele to mean genes which have different effects
on a single characteristic that are at the same loci on homologous 
chromosomes.

Is the actual locus of a gene on the genetic strip important ?
From what I understand I don't think it is because a gene will either always
be expressed (ie. it's constitutive) or it will be turned on or off by other
genes and this is controlled by what the gene or its promoter looks
like not its actual position on the strip.

So if the position isn't important why should alleles be in the same
position on different chromosomes ? Why should they even be the same length ?
(Indeed, are they the same length ?) Is crossover the mechanism that forces
genes with similar effects to reside at the same locus ? ie. does crossover
force alleles ?

If, by inversion, an allele of a gene is moved from one locus to another
position, is it still an allele ? If it is, then the whole definition of
alleles seems, to me, to be inconsistent.

Is the garbage information that now fills its old locus an allele ? If it
isn't (as I would expect) then does that mean that at a particular locus one
finds either alleles of a gene, garbage or other genes ? 

Is it right to say that base pairs in the promoter region of a gene can
serve as some kind of signature for that gene ? For example, if an enzyme
wants to repress a gene for short hair and the promoter region for the
short hair gene always contains the sequence AAATTGGGTACG then can the
enzyme only look for this sequence rather than a much longer one that is
the actual gene itself ?

Must each of the alleles of a particular gene have the same information
in the promoter sequence ? By that I mean, do all alleles of a gene have to
be turned on in the same way and have the same signature ?

Thanks in advance for anyone who can help me.


Regards,

Paul Kennedy

School of Computing Science,
University of Technology, Sydney.
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Paul Kennedy - paulk@socs.uts.edu.au
School of Computing Sciences, University of Technology, Sydney.
PO Box 123 Broadway NSW 2007 Australia.