Three paralogues in lampreys and gnathostomes-brothers or cousins?

is a key regulator of the early development of the vertebrate forebrain and sensory organs. In this study, we describe for the first time three paralogues in lamprey, representative of one of two basally diverged lineages of vertebrates-the agnathans. We also first describe three genes in sterlet-representative of one of the evolutionarily ancient clades of gnathostomes.