Christopher G Winter <cgw1 at columbia.edu> wrote:
I have a problem which begins with the fact that I have a nearly
complete ignorance of genetics. My question is: To what extent is the distance
between two particular, unrelated genes conserved between eukaryotic
species. If one finds that gene X and gene Y are close together in the
genome of mouse, would you expect that the human homologues of gene X and
gene Y would also be closely linked, or would you expect that their
positions would be shuffled in the absence of some selective pressure to
maintain their linkage? Some related genes tend to be found in groups
due , I suppose, to recent gene duplication events (I'm told this is true
for some of the members of the interleukin family).But what about genes
with no sequence homology to each other?
I would be grateful if someone could set me straight on this, or
at least point me in the right direction in terms of finding references
which would answer this question.
Thanks in advance,
Chris
Response:
There's a fair bit of conservation of gene order, which is really
handy for gene mapping. A nice poster showing the mouse genome map and
its human parallels is in Science 1st October 1993 - I have a copy from
the Gibco-BRL company. A simple summary of the mouse-human
relationship would be that one chromosome of
one species generally corresponds to 5-10 chunks of different chromosomes
from the other species. Within these chunks, gene order is generally
conserved.
There is a www page about comparative mammalian genome maps:
http://www.informatics.jax.org
This is reviewed on pp363-365 of Nature 26th Jan 1995.
If you're interested in plants, most of the cereals have very similar
gene maps (the technical word for parallel gene order is 'synteny'). A
little article on this by Robert Shields is on pp297-298 of Nature 23
Sept. 1993.
Adam Marchant
Agricultural Research Institute
Wagga Wagga
NSW Australia
marchaa at agric.nsw.gov.au
