Use this field to specify additional variables across the meta-analysis that contain chromosome identifiers.This field is used only when one or more of the data sets selected, after the first, uses a variable with another name for the Chromosome Variable. All variable names for the 2nd through the last data set must be specified here.
For example, to specify the additional chromosome variables Chr_1 and Chr_2, type Chr_1 Chr_2 in the text box, as shown below: