Step 2. Choose variables
        
           [required] CHR, one.  This column indicates the chromosome on which the genetic variant (also known as a SNP) is located.
           [required] POS, one. This column specifies the exact position of the variant on the chromosome.
           [required] PVAL, one. The p-value indicates the statistical significance of the observed effect.
        
        
         Step 3. Plot!