In article <2l8g2k$odr at canopus.cc.umanitoba.ca>
xia at cc.umanitoba.ca (Xuhua Xia) writes:
>Chromosome is a relatively stable genetic entity, yet different species,
>even sister species, could differ much in the haploid number. [...]
>To do this we need to know which chromosome
>from one species (say mouse) is analogous to which chromosome from another
>species (say human). [...]
What you are talking about is called karyotype evolution.
It is extensively studied in many taxonomic groups.
Establishment of so-called "syntenic" relationships is an
ongoing effort in the human genome initiative in part because of
the potential that human disease genes will have mouse or rat homologs
that are experimentally manipulable. Mammalian karyotype evolution
studies involve cytogenetics of chromosome banding patterns and
linkage assignments of functionally homologous genes (i.e., enzyme
genes, other biochemical loci, cloned DNAs, etc.) and anonymous
sequence-tagged-sites that are adventitiously conserved between species.
Another highly successful example involves cytological studies
of karyotype evolution in members of the Drosophila genus. Inversions,
transpositions, centromere-fusion/fission events, are all associated
with species divergence and contribute greatly to taxonomic & phylogenetic
assignments of subgenera, species-group, etc.
--
Mark D. Garfinkel (e-mail: garfinkl at iitmax.acc.iit.edu)
My views are my own, which is why they're copyright 1994
