A new method for detection of small modifications in genomic DNA, applied to the human delta-beta globin gene cluster.
Cloned DNA fragments were subcloned in filamentous coliphages fd 103 or M 13; the recombinant single-stranded DNAs were then used to form hybrids with genomic DNA as well as with complementary recombinant single-stranded DNA. Hybrids were submitted to S1-nuclease treatment alone or in combination with restriction enzyme digestions. This method was used to analyze the delta-beta globin gene cluster from the total genomic DNA of a beta 0-thalassemic patient. A modification located approximately 530 base pairs upstream from the cap site of the beta-globin gene was detected in only one thalassemic chromosome of this patient. Sequence analysis have shown that the patient was homozygous for a single nucleoside change (dC----dT) which remains undetected by our hybridization method, leading to a codon 39 nonsense mutation; they have demonstrated too that he was heterozygous for the modification mentioned and detected by S1-nuclease, which corresponds to an additional sequence d(T-A-T-A) in a 52 alternating purine-pyrimidine run, leading to a complex change from d[(A-T)7(T)7] to d[(A-T)11(T)3].
D001483:Base Sequence; D004274:DNA, Recombinant; D004720:Endonucleases; D005796:Genes; D005914:Globins / Q000235:genetics*; D006801:Humans; D009154:Mutation; D009693:Nucleic Acid Hybridization; D015719:Single-Strand Specific DNA and RNA Endonucleases; D013789:Thalassemia / Q000235:genetics*
D004274:DNA, Recombinant; D005914:Globins; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases