Preparation of Traditional Nucleic Acid Probe
                Amino acid sequence
                    GLY-ASP-GLU-SER-SER-VAL-LEU-----
                   GGG-GAC-GAG-TCC-TCC-GTT-CTC---
                    *     *        *     *     *     *     *
                 Nucleic acid sequence             * Codon degeneracy
   The nucleic acid sequence is             Synthesizing
   Deduced from amino acid sequence         oligonucleotide
                 Chemical synthesis
             PROBE: GGGGACGAGTCCTCCGTTCT
             PROBE: GGGGACGAGTCCTCCGTTCT
                                                                Juang RH (2004) BCbasics
    Probe is labeled with radioactive 32P
                              GGGGACG           Hybridization
                          32              AG
                           P                 TC
                                                CT
                                                  C
                                                   C             T
                                                    G           A
                                CTG                   T   T
                                                       T
                             CC      CTC                C      C
                           C              A                  G
                          T                G                G
                         A                   G            A
                                               A        G
                                                G      A
                                                  G A
                      CC                            C
                   AT
                  G
                 G
                                 DNA             Target gene
                             denaturation
                  Single colony
                                       Lysed
                                                                Juang RH (2004) BCbasics
   Colony Is Screened by Hybridization with Probe
                            Colony hybridization
                                 Cover with
                                 filter paper      Transferring …
                                    Collect filter 
                                        paper
                                              Dissolve cell    DNA denatured
         Autoradiography                                      Add probe
                                                                                s
                                                                                c
                                                                                i
                                                                                s
                                                                                a
                                                                                b
                                                                                C
                                                                                B
                                                                                 
                                                                                )
                                                                                4
                                                                                0
                                                                                0
                                                                                2
                                                                                (
                                                                                 
                                                                                H
                                                                                R
                                                                                 
                                                                                g
                                                                                n
                                                                                a
                                                                                u
                                                                                J
                                                   Biochip Based on Hybridization 
                                                    Sample DNA
                                                                    Complementary DNA hybridize
    Biochip
   Each spot contains known DNA
                                                                                     Signal appears
  Schena (2000) Microarray Biochip Technology, p. A31                                                 Juang RH (2004) BCbasics