Markers

The chromosome 14 markers were all inter-Alu sequences - short stretches of unique DNA sequence which are flanked in the genome by Alu repeat elements:

Markers of this type were used mainly because the mapping panel was amplified using Alu PCR (a form of repeat-PCR), which meant that only inter-Alu marker sequences could be typed.

Marker sequences were obtained by using Alu PCR to amplify bulk DNA prepared from hybrid cells containing human chromosome 14 in a rodent background. Since the rodent chromosomes lack Alu elements, only human-derived sequences were amplified. These PCR products were then cloned and sequenced to obtain suitable target sequences for marker design. Additional marker sequences were obtained from flow-sorted human chromosome 14, again amplified by Alu PCR, cloned and sequenced.