The chromosomal distribution of repetitive DNA sequences within the human beta globin gene cluster

The chromosomal distribution and degree of repetitiveness of the sequences within the human beta globin gene cluster has been studied by in situ hybridisation. A genomic recombinant, H beta G1, which contains 15.9 thousand base pairs (kb) of DNA inserted into lambda charon 4A, was used as a template for the [3H] complementary RNA used for hybridisation. The inserted DNA contains sequences 4.7 kb to the 5' side of the delta gene and continues through the delta and beta genes to a site 2.8 kb to the 3' side of the beta gene. Two highly repetitive sequences, which are distributed evenly over all the chromosomes, have been identified within this DNA. Another somewhat less repetitive sequence has been identified between the beta and delta genes.