[BioC] downloading a conservation track with rtracklayer on several chromosome seqs

[Dario Strbenac]

> > dear list,
> >
> > i'd like to know how can i download the conservation track for several
> > genomic ranges belonging to different chromosome sequences
> 
> This is not supported yet, mostly because whenever people have multiple
> regions, they have a lot of regions, and the current, simple implementation
> would be too slow. It is possible though to upload a track to UCSC and ask
> it for the regions that intersect that track. I'll put that on the TODO
> list; actually it was already on there. For now, you might just have to loop
> in R and make separate requests.

Is there a small, complete example of doing this with the current version of rtracklayer ? I also have a lot of regions.