Figure 1

Physical positions of microsatellite markers used in genetic mapping. The three chromosomes are indicated as horizontal lines (from top: X, 3, 2), and positions of marker loci are vertical lines labeled with the marker name. Note the high density of markers on chromosome 2L (boxed section expanded in bottom horizontal line, labeled 2L box), which were used to map at greater density once an initial linkage signal was detected. Dense markers were necessary so that the most informative markers (i.e., those with the greatest numbers of alleles segregating) could be used in the analysis. The five clustered marker loci giving significant linkage (linkage data shown in Table 1) are depicted in bold red type and are starred. For comparison, the extent of the Plasmodium-resistance island mapped in West African pedigrees [4] is indicated by the filled bar above chromosome 2L (labeled PRI). Chromosome 2 is shown in the 2La inverted (2La/a) conformation.