🚀 go-pugleaf

In article <greg.dressler-0312941733380001@229.32.med.umich.edu>,
greg.dressler (Greg Dressler) writes:
>[snipette]
>The position of genetic loci are not measured in base pairs, the are
>positioned on a genetic map of each chromosome.  Thus, each gene is
>positioned only with respect to other genes.  The distances between genes
>are expressed in centi-Morgans (after the great geneticist Thomas Morgan)
>and these distances are not actual physical lengths, rather they represent
>recombination frequencies between genes.
>
	One of the difficulties in the human genome project (HUGO) is the rec-
tification of the genetic distance with the physical distance, and the location
in base pairs *is* important to understanding the genome as a whole.

>[snipette]
>There is no obvious reason why genes are where they are.

	Thus finding clues from the locations as to why genes are where they
are is important to understanding the details of their function.

>[snip]  
>Humans have all the same genes at the same loci, that is what makes us
>human.                                            

	Unless there are some genes which are actually missing.  I don't know
of an example, but if a region of DNA which contained a previously functioning
gene which was non-essential for survival, e.g. hair color, was eliminated by
uneven crossing over, the resulting being--indistinguishable from humans who
have a (possibly non-functioning) gene at that locus--would still be considered
human.  There are a lot of places in the genome which do not produce anything,
but which may have a function that we do not know about, or which may mutate
to a useful gene in the future--a number of proteins are thought to have evol-
ved by gene duplication and mutation.  Possibly some of these duplicated reg-
ions have more repeats in one individual than another.
				Yours,
				Bill Tivol