Several methods have been published that rely on the use of short oligonucleotide primers with arbitrary sequences to amplify discrete DNA fragments by the polymerase chain reaction (PCR) (1,2). Typically, a single arbitrary primer is used in each reaction and amplification is achieved when the same sequence is present in inverted orientation at two sites separated by less than a few kilobases. These methods have several advantages:

1.	They can be used to produce quickly large numbers of discrete DNA fragments without prior sequence information;
2.	Owing to the random nature of the process, the amplified fragments are likely to be evenly distributed across a genomic region;
3.	Because they do not rely on the presence of species-specific repetitive sequences (e.g., Alu repeats [3]), they can be used to analyze the genome of any species.