Repetitive DNA sequences within and around the rat prolactin gene

Repetitive DNA sequences in and around the rat prolactin gene were identified and mapped by hybridizing labeled total rat DNA to cloned prolactin DNA and by hybridizing labeled prolactin DNA fragments to total restricted rat DNA. Repeated sequences were found 12-8 and 2.5-0.5 kb upstream of the first exon, within the fourth intron and throughout almost the entire 15.5 kb of cloned DNA downstream from the last exon. By cross-hybridization of the major repeated sequences, it was found that these repeats could be grouped into three families, one of which is novel. Human alu and mouse alu-like probes did not hybridize to the rat prolactin DNA. Several of the repeats from the rat prolactin gene hybridized to the intron and downstream flanking regions of the rat growth hormone gene.