Comparison of relative hybridization data between RNA expression profiling and comparative genomic hybridization. RNA or genomic DNA derived probes were prepared from L. major MTX60.4 and the sensitive parent strain and hybridized to DNA microarrays. A subset of whole chromosome comparisons showing the correlation between RNA and DNA hybridization data are depicted. Examples shown are: chromosome 1 used as a no change control; chromosome 6 and the overexpression/amplification of the DHFR-TS locus (for quantification see Figure 4); and chromosome 22, where DNA and RNA are increased. For chromosome 11, RNA is decreased while DNA appears the same but the latter was also confirmed by Southern blots (Figure 7).