Paten B, Diekhans M, Earl D, John JS, Ma J, Suh B, Haussler D.

J Comput Biol. 2011 Mar;18(3):469-81. doi: 10.1089/cmb.2010.0252

Cactus graphs for genome comparisons.

Alignments are transformed in sequence graphs where nodes are connected by either alignment blocks or adjascencies between blocks, and this graph is progressively transformed in a cactus graph where the nodes are sets of adjascencies connected together without crossing a block.