Phenotypic and molecular markers mapped on human chromosome 1

The diagram shows the distribution of all genetic differences that had been mapped to chromosome 1 at the time at which this diagram was drawn. Some markers are genes of known phenotype (their numbers are shaded in green), but most are polymorphic DNA markers (the numbers shaded in mauve and blue represent two different classes of molecular markers). A linkage map displaying a well-spaced-out set of these markers, based on recombinant frequency analyses of the type described in this chapter, is in the center of the illustration. Map distances are shown in centimorgans (cM). At a total length of 356 cM, chromosome 1 is the longest human chromosome. Some markers have also been localized on the chromosome 1 cytogenetic map (right-hand map, called an idiogram), by using techniques described later in this chapter. Having common landmark markers on the different genetic maps permits the locations of other genes and molecular markers to be estimated on each map.

[Data from B. R. Jasny et al., Science, September 30, 1994]