different genes or splice variants?

[Kevin Karplus]

In article <agj3gp$mo$1 at mercury.hgmp.mrc.ac.uk>,
> Tobias McNultey wrote:
> > I  looked for  the ortholog of  a  gene in 
> > Drosophila,
> > (where  there is  only one member of this  gene 
> > family)
> > in  another genome, Anopheles gambiae.
> > 
> > I  found the ortholog  but also two other isoforms
> > of this  gene.
> > Three isoforms *adjacent* to each other  on the
> > chromosome.
> > What's  more, the   intron/exon  boundaries
> between 
> > the
> > two most  similar  are conserved! 
> > Can someone  tell me  if  this is novel? I   don't
> > know  where to look.
> > I  have heard of clustering but these  are right
> > next to each other.
> > It  is  not alternative splicing  right?
> > I  observe:
> >   
> >
>
-------A------------B------------C------------------a----b------c---
> > 
> >  where A and  are  homologous exons. If you had 
> >  alternativeplicing  the 
> >  genomic orgization would be different, right?  I
> >  would expec this:
> >  
> >
>
--------A--------a-------B--------b--------C--------c-----
> >>  Can someone  clue me in. I am  just  getting
> > started
 
What you have is sometimes referred to as "tandem
duplication".  It is
a very common mechanism for gene duplication.  You
have apparently
found one that is relatively recent, as the genes
have not drifted
much from being exact copies and other species have
only one copy of
the gene.  Some researchers have been using this
sort (and other
sorts) of gene duplication as a way to generate
evolutionary trees.

-- 
Kevin Karplus 	karplus at soe.ucsc.edu
http://www.soe.ucsc.edu/~karplus
life member (LAB, Adventure Cycling, American Youth
Hostels)
Effective Cycling Instructor #218-ck (lapsed)
Professor of Computer Engineering, University of
California, Santa Cruz
Undergraduate Director, Bioinformatics
Affiliations for identification only. 

=====



Moderated
bionet.genome.gene-structure



__________________________________________________
Do You Yahoo!?
Everything you'll ever need on one web page
from News and Sport to Email and Music Charts
http://uk.my.yahoo.com