Comparative Mapping and Genome Rearrangement

Comparative mapping of two species allows the observation of chromosomal segments conserved in both genomes since divergence from a common ancestor. Statistical analysis of the distribution of genes in these segments leads to an estimation of the number of unobserved segments, i.e., those containing no homologous genes identified as yet in the two genomes, possibly far more numerous than the observed ones. The total number of segments, observed and unobserved, is a measure of the evolutionary divergence of the two species. The algorithmic study of genome rearrangements focuses on the combinatorics of which segments are adjacent to which others in each genome and estimates the number of translocations and/or inversions necessary to account for the observed configuration. This has extensions to the study of gene families, genome duplication and hybridization. We review recent developments in both fields and assess the potential for an integrated approach.