The Oligomer Restriction technique was developed as a variation of the Restriction Fragment Length Polymorphism (RFLP) assay method, with the hope of avoiding the laborious Southern blotting step used in RFLP analysis. OR was conceived by Randall Saiki and Henry Erlich in the early 1980s, working at Cetus Corporation in Emeryville, California. It was patented in 1984 and published in 1985, having been applied to the genomic mutation responsible for Sickle Cell Anemia. OR was soon replaced by the more general technique of Allele Specific Oligonucleotide (ASO) probes.