The genomic 'inner fish' and a regulatory enigma in the vertebrates.

Information on how genomic information from fish to human encodes the same tissues has until now emerged one gene at a time. The study published in this issue now provides lists of genes and their expression levels for 20 vertebrate tissues spanning 450 million years of vertebrate evolution. It reveals a core set of genes with similar tissue-expression patterns yet no common regulatory signatures--a gene-expression paradox.