_IMG_21_06MicroarrayChip-L.jpg A DNA microarray contains hundreds of thousands of single-stranded DNA placed on a glass chip. _SPAN_bed cDNA is made from an individual's _SPAN_ORANGE mRNA. The _SPAN_bed cDNA is then hybridized to the _fig_ch20/microarray.html array to analyze that person's genotype. This chip represents all the known alleles in the human genome.