Removing noise and ambiguities from comparative maps in rearrangement analysis

Comparison of genomic maps is hampered by errors and ambiguities introduced by mapping technology, incorrectly resolved paralogy, small samples of markers, and extensive genome rearrangement. We design an analysis to remove or resolve most of these problems and to extract corrected data where markers occur in consecutive strips in both genomes. To do this, we introduce the notion of prestrip, an efficient way of generating these and a compatibility analysis culminating in a Maximum Weighted Clique (MWC) search. The output can be directly analyzed with genome rearrangement algorithms, allowing the restoration of some of the data not incorporated into the clique solution. We investigate the trade-off between criteria for discarding excessive prestrips to make MWC feasible in terms of retaining as many markers as possible in the solution and producing an economical rearrangement analysis. We explore these questions through simulation and through comparison of the rice and sorghum genomes.