QUANTITATIVE MONITORING OF GENE-EXPRESSION PATTERNS WITH A COMPLEMENTARY-DNA MICROARRAY

A high-capacity system was developed to monitor the expression of many genes in parallel. Microarrays prepared by high-speed robotic printin g of complementary DNAs on glass were used for quantitative expression measurements of the corresponding genes. Because of the small format and high density of the arrays, hybridization volumes of 2 microliters could be used that enabled detection of rare transcripts in probe mix tures derived from 2 micrograms of total cellular messenger RNA. Diffe rential expression measurements of 45 Arabidopsis genes were made by m eans of simultaneous, two-color fluorescence hybridization.