A CLUSTER OF CUTICLE PROTEIN GENES OF DROSOPHILA-MELANOGASTER AT 65A - SEQUENCE, STRUCTURE AND EVOLUTION

A 36-kb genomic DNA segment of the Drosophila melanogaster genome cont aining 12 clustered cuticle genes has been mapped and partially sequen ced. The cluster maps at 65A 5-6 on the left arm of the third chromoso me, in agreement with the previously determined location of a putative cluster encompassing the genes for the third instar larval cuticle pr oteins LCP5, LCP6 and LCP8. This cluster is the largest cuticle gene c luster discovered to date and shows a number of surprising features th at explain in part the genetic complexity of the LCP5, LCP6 and LCP8 l oci. The genes encoding LCP5 and LCP8 are multiple copy genes and the presence of extensive similarity in their coding regions gives the fir st evidence for gene conversion in cuticle genes. In addition, five ge nes in the cluster are intronless. Four of these five have arisen by r etroposition. The other genes in the cluster have a single intron loca ted at an unusual location for insect cuticle genes.