The data file hg17ToHg18.over.chain.gz is a mirror of UCSC's corresponding LiftOver chain file.
Original file can be found at:
    * https://hgdownload.cse.ucsc.edu/goldenPath/hg17/liftOver/
The data is released for free use by UCSC
    * http://genome.ucsc.edu/goldenPath/credits.html#human_credits
