Genomic regulatory blocks are chromosomal regions spanned by long clusters of 
highly conserved noncoding elements devoted to long-range regulation of 
developmental genes, often immobilizing other, unrelated genes into long-lasting 
syntenic arrangements. Synorth http://synorth.genereg.net/ is a web resource for 
exploring and categorizing the syntenic relationships in genomic regulatory 
blocks across multiple genomes, tracing their evolutionary fate after teleost 
whole genome duplication at the level of genomic regulatory block loci, 
individual genes, and their phylogenetic context.