STRUCTURE AND POLYMORPHISM OF RIBOSOMAL-RNA GENES IN THE MARINE SHRIMP PENAEUS-VANNAMEI

We have examined the structure and polymorphism of the genes that enco de ribosomal RNA in the Pacific whiteleg shrimp, Penaeus vannamei. We have found that the rRNA genes are polymorphic within and between indi vidual shrimp and between selectively bred families. The polymorphism suggests the presence of repeated DNA sequence elements in the interge nic spacer region upstream from the promoter for transcription of the rRNA genes. In other organisms, such repeated elements have been shown to serve as alternative promoters or enhancers for transcription. If the same is true in P. vannamei, the observed polymorphism might be li nked to traits important for shrimp aquaculture. (C) 1998 Elsevier Sci ence B.V.