Mapping panels

The main human mapping panel was prepared by irradiating agarose-embedded human DNA to produce random breaks, then size fractionating the products by pulsed-field gel electrophoresis. A set of 96 aliquots were taken, each containing about 2pg (0.7 genomes) of ~1-2Mb DNA fragments.

These aliquots were pre-amplified using Alu-PCR, a form of repeat PCR based on the Alu repeat elements which are common in the human genome. This yielded sufficient material to type many thousands of markers on each aliquot using marker-specific primers, though it also restricted marker choice - only inter-Alu sequences could be used as markers. (For other methods of mapping panel amplification, see the methods section.)

The longer-range panels, which were made from larger fragments in order to close the remaining gaps in the map, were prepared in the same way.