Synteny blocks are composed of two or more orthologous genes conserved among 
species, resulting from speciation from their last common ancestor. OrthoCluster 
(Zeng et al., 2008) is a fast and easy-to-use program for the identification of 
synteny blocks among multiple genomes. It allows users to identify synteny 
blocks that contain different types of mismatches, and to decide whether they 
require conservation of gene orientation and conservation of gene order within 
the blocks. OrthoCluster can also be used to find duplicated blocks within 
genomes. Although genes and their correspondence are usually used as input for 
OrthoCluster, in fact, OrthoCluster can be applied using any type of markers as 
input as long as their relationships can be established. OrthoClusterDB provides 
a Web interface for running OrthoCluster with user-defined datasets and 
parameters, as well as for browsing and downloading precomputed synteny blocks 
for different groups of genomes.