To evaluate the overlap of significantly (padjusted < 0.01) altered transcripts between the sensitive and resistant collectives we formed a two-way table. A TCDD-responsive score of -1 (repressed), 0 (unchanged), or +1 (induced) was assigned to each gene in each strain. The sum of the scores for the sensitive strains/lines form the columns and the sum of the scores for the resistant strains/lines are the rows. Each value corresponds to the number of genes that exhibited a significant response to TCDD treatment. For example, 20 genes are induced in both sensitive and both resistant strains/lines, while 5 genes are repressed in both of the sensitive strains/lines and both of the resistant strains/lines. Of the 8605 genes examined, 452 genes responded in at least 1 strain/line, while 8153 genes did not respond to TCDD in any rat strain/line.