A plurality of cDNAs each having a known different base sequence are
labeled with a fluorescent dye (FITC), whereby F-cDNA is prepared. The
F-cDNA is disposed at a plurality of predetermined positions on the slide
glass of a DNA micro array chip. Cy5-cDNA is prepared by synthesizing cDNA
from poly(A)-mRNA in the presence of a fluorescent dye (Cy5). The Cy5-cDNA
is placed on the DNA micro array chip and hybridized to the F-cDNA. After
hybridization, the DNA micro array chip is read by a quantitative
apparatus incorporated with an analyzer in which information about the
base composition ratio and base length of cDNA has been registered.
