Two engrailed-related genes in the cockroach: cloning, phylogenetic analysis, expression and isolation of splice variants

engrailed-related genes have been isolated in numerous taxa. Within the ins ects, some species have a single engrailed-related gene whilst others have two copies, raising the question of when and how often gene duplications ha ve occurred. Here we report the cloning, in the cockroach Periplaneta ameri cana, of two engrailed-related genes Pn-en1 and Pa-en2 By comparing conserv ed domains and by carrying out a phylogenetic analysis, we conclude that th ese two genes are likely to be the product of a recent duplication in the c ockroach lineage. Pa-en1 and Pa-en2 are co-expressed during early embryogen esis and their segmental pattern of expression appears in an anterior-poste rior progression. We have also isolated potential splice variants of Pa-en2 which lack some regulatory domains. The roles these splice variants may pl ay in regulating developmental processes are discussed.