Trichinella spiralis: cloning and characterisation of two repetitive DNA sequences.

Digestion of genomic DNA of Trichinella spiralis with EcoRI reveals the presence of several families of repetitive DNA. Two small repeats of 516 and 604 bp, respectively, have been cloned and sequenced. The two repeats are related to each other and to a 1.1-kb repetitive DNA. Similar sequences are not detected in other species by hybridisation. There are about 270 copies of each small repeat per haploid genome and these are organised in large arrays of > or = 50 kb. The basic repetitive unit appears to contain one copy of each repeat. This repetitive DNA is transcribed in muscle-stage larvae although it is not protein coding.