Nature Reviews Genetics 4, 937–947 (2003); doi: 10.1038/nrg1229

The glossary definitions for 'Map-based' and 'Sequence-based' were incorrect. The correct definitions should have read:

MAP BASED An approach to genetic-association studies that is focused on a set of genetic markers, often now called tagging SNPs, which are statistically associated with whichever variants influence the phenotype.

SEQUENCE BASED An approach to genetic-association studies that is focused on putatively functional SNPs, for example, identified by re-sequencing exons and other functional regions in relatively large samples, or directly in patients. This approach is also sometimes called direct.

Also the last sentence in the legend for Figure 2: 'Illustration of tagging SNPs' contained an error and should have read:

However, because the pattern of association has changed, the new haplotypes 6 and 7 are misclassified as haplotype patterns 2 and 3 in population B.