INCREMENT OF EFFICIENCY IN THE IDENTIFICATION OF NOBLE GENES BY COLONY HYBRIDIZATION ASSAY (SCREENING OF LOW REDUNDANT CLONES FROM HUMAN FETAL CDNA LIBRARY)

For the rapid identification of noble genes in a specific tissue by co mputer analysis from the cDNA sequences determined by single-pass cDNA sequencing, clone redundancy was one of the major obstacles. To facil itate the efficiency in identification of noble genes, it was necessar y to reduce the number of clones to be sequenced by eliminating the re dundant clones for a rapid analysis. In order to increase the probabil ity of isolating noble sequences from the cDNA clones of human fetal l iver tissue origin, colony hybridization assay was adopted and redunda nt clones were efficiently removed. Four cDNA clones highly redundant in the human fetal liver cDNA libraries including alpha-globin, gamma- globin, serum albumin and H19 RNA sequences were selected as the probe s. Two hundreds and sixty two cDNA clones were randomly selected and t ested with the probes for hybridization properties. The identity of ea ch cDNA clone giving positive or negative signals in the hybridization assay was determined by DNA homology search with the nucleic acid dat abases. Among the 76 clones giving positive signals, 57 clones (75%) w ere found to be identical to the probe sequences and could be eliminat ed by colony hybridization assay before neucleotide sequencing.