title: A direct estimate of the number of human gamma-globin genes.
abstract: The number of genes specifying human gamma-globin has been determined directly by hybridization of complementary DNA to total human DNA. The complementary DNA was enriched in sequences specific for gamma-globin genes by transcribing globin mRNA isolated from fetal reticulocytes with viral reverse transcriptase, and collecting the material which does not back-hybridize to adult globin mRNA. When hybridized in cDNA excess to DNA, very similar values are found for gamma-gene number as for beta-gene number, suggesting two or at most three gamma-globin genes per haploid human genome. This indicates that the non-Mendelian ratios of gamma-chain mutants found in heterozygotes are due to transcriptional or post-transcriptional regulation rather than to gene dosage. The number of each major human globin gene has now been determined directly by molecular methods.
mesh_terms: D005796:Genes; D005914:Globins / Q000096:biosynthesis*; D006801:Humans; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D005914:Globins