Individuals are assigned to populations based on the specimen metadata data file (csv) used with gl.read.dart().
Recoding can be used to amalgamate populations or to selectively delete or retain populations.
The population recode file contains a list of populations in the genelight object as
the first column of the csv file, and the new population assignments in the second column of the csv file.
The keyword Delete used as a new population assignment will result in the associated specimen being dropped from the dataset.
The script, having deleted populations, optionally identifies resultant monomorphic loci or loci
with all values missing and deletes them (using gl.filter.monomorphs.r). The script also optionally
recalculates the locus metadata as appropriate.