Demonstration of Two alpha-Globin Genes per Human Haploid Genome for Normals and Hb J Mexico

Abstract
Complementary DNA (cDNA) was prepared with viral RNA‐dependent DNA polymerase using human globin messenger RNA (mRNA) as template. By selective hybridization to globin mRNA from β‐thalassaemics a probe which was > 85% complementary to α‐globin mRNA was purified. This was hybridized in cDNA excess to human genomic DNA, and the rate and extent of hybridization confirmed that there are two genes for α‐globin per haploid genome. Cellular DNA was also prepared from peripheral blood from cases expressing the α‐globin chain mutant Hb J Mexico to varying extents. This DNA was identical in hybridization behaviour to normal DNA demonstrating that the imbalanced mutant chain synthesis seen physiologically is not due to a gene deletion.