5 µm

Millions of copies of a specificoligonucleotide probe

>5 760,000 differentcomplementary probes

~260 000 targets

Single stranded, labeled ‘target’

Oligonucleotide ‘probe’* *** *

1.28cm

GeneChip Probe Array

Hybridized Probe Cell

1.28cm

Probe Construction

GeneChip® Expression Analysis Procedures for Target Preparation

cDNAFragment(heat, Mg2+)

B B B B

Wash & StainScan Hybridize

(16 hours)

Biotin-labeled transcripts

RNA

AAAA

IVT

(Biotin-UTPBiotin-CTP)

Fragmented cRNA

B B

B

B

Cells