A genetic map of chromosome 1: comparison of different data sets and linkage programs.

We have used 22 chromosome 1 loci to construct a genetic linkage map of this autosome using the Venezuelan Reference Pedigree. These markers formed two linkage groups separated by an interval of more than 30 cM. Linkage maps were constructed separately using the computer programs LINKAGE and MAPMAKER to determine their relative speed, efficiency, and accuracy. We found that both programs generated maps with the same order and distances, although the LINKAGE program derived more information from the data, allowing placement of one additional marker. Many of the probes have previously been mapped using the CEPH pedigrees. However, the current map is generated from a different data set and so can be used to increase the certainty of locus order and map position. Ultimately, the generation and confirmation of a 1-cM map of this chromosome will require such multiple data sets.