The tracks indicated by the logo
have been lifted from hg18 or hg17, respectively, with a minimum of quality-control
scrutiny. They are provided to our users with the intent that
they assist in interpretation of other data, but must be used
with caution. Not all annotations remain intact
when lifted in this manner and in any case, cannot by definition
contain any sequence that is new to hg19.
It should also be noted that tracks containing large regions will
lift less well because of the increased chance of spanning a region
that changed between the two assemblies.