A cloned AluI-equivalent repetitive sequence that detects transfected hamster DNA

An AluI-equivalent interspersed repetitive element showing 75% homology to a published consensus sequence, which is present at a level of 3 x 10(5) copies per hamster genome [Haynes et al., Mol. Cell. Biol. 1 (1981) 573-583], has been cloned into plasmid pUC8 as a tandem copy which can be readily excised, self-ligated and labelled for use as a hybridisation probe. This probe successfully detects integrated hamster sequences in the DNA of transfected human cells [Arrand et al., Proc. Natl. Acad. Sci. USA 86 (1989) 6997-7001], whereas repetitive hamster DNA isolated as a C0t = 1 (fast reannealing) fraction fails to do so. Hamster DNA-containing clones in genomic libraries derived from hamster/human hybrids are also easily detected with this probe, thus facilitating the isolation of hamster genes which complement human gene defects.