Changes in restricted human cellular DNA fragments containing globin gene sequences in thalassemias and related disorders

Abstract

Human cellular DNA fragments from cells of normal subjects and patients with thalassemia obtained by restriction enzyme digestion were analyzed for their globin gene content. The fragments were separated on agarose gels, transferred to nitrocellulose filters, hybridized to globin [32P]c[complementary]DNA and autoradiographed. One to ten picograms of globin gene sequences were detectable. With EcoRI digestion 8-9 cellular DNA fragments contained globin genes. Three of these contained .beta.-like gene sequences assayed with a .beta. globin cDNA probe. One .beta.-like fragment was absent in DNA from a homozygous subject for Hb Lepore. Two of the 3 .beta. gene-containing fragments present in normal DNA were absent in DNA from a patient with hereditary persistence of fetal Hb. The same 2 fragments containing .beta.-like genes were absent from .delta..beta. thalassemic DNA and 1 new fragment containing .beta.-like genes was found. Together with results obtained by hybridization of these DNA in solution, the data are consistent with deletion of specific restriction human DNA fragments in subjects with these disorders and a greater deletion of .beta.-like gene sequences in subjects with hereditary persistence of fetal hemoglobin than in those with .delta..beta. thalassemia.