Hello Avi,

If you type in the command at the prompt, a list of options will appear 
along with usage. The over.chain files are in Downloads, ftp directory 
goldenPath/<from_species>/liftOver/.

For default genomic examples, there are two classes: same species lifts 
and cross-species lifts. Both can be seen in the web version [UCSC 
Browser home page -> Utilities -> Batch Coordinate Conversion 
(liftOver)] http://genome.ucsc.edu/cgi-bin/hgLiftOver

The most basic option for genomic would be to set -minmatch = 0.95 for 
same-species and = 0.1 for cross-species and leave the rest as default.

For any failures, you can examine the reasons and play around with the 
parameters, such as setting multiple = Y. But beware that this can 
produce significant output if minmatch is low and chain and hit size are 
set >= 0. It will probably take a few attempts to tune these in various 
combinations so that the output is useful for your particular needs.

The other options come into play for gene, transcripts and other 
annotation types that are lifted. Again, the program runs pretty fast 
even on large datasets, so a cyclic test-and-analyze approach is 
probably the best way to find your own best parameters to create useful 
lifted data.

FAQ in case you have not seen it: 
http://genome.ucsc.edu/FAQ/FAQdownloads#download28

Good luck and please write back if you need more technical help,
Jennifer Jackson
UCSC Genome Bioinformatics Group

Fungazid wrote:
> hello genome browser staff,
>
> I would like to map species A genomic coordinates to species B genomic 
> coordinates (e.g. mouse -> human). To my knowledge liftover can do it (I also 
> tried to workaround by blating the query region with gfserver/gfclient, but 
> this is too slow for large tables). I have Liftover installed on Linux, but I 
> didn't find any documentation about input parameters and examples. 
> Maybe you can help, or direct me to a proper documentation. 
>
>
> Thanks, (also you for your previous help)
> Avi
>
>
>       
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