Figure 1

Examples of the wave artifact and the fitted loess curve. In the two left hand plots we display the log₂ ratios for clones on the long arm of chromosome 1 plotted against their genomic location for two HapMap samples, NA06993 (top) and NA11832 (bottom). On the right we plot the log₂ ratios for clones on a section of the long arm of chromosome 15 against their genomic location for samples NA06993 (top) and NA11832 (bottom). The wave effect can be observed by scanning across each of the plots from left to right. The fitted loess curves for each of these samples/genomic regions have been overlaid in blue.