RAPD-PCR INVESTIGATIONS ON SIBLING SPECIES OF TERRESTRIAL ENCHYTRAEUS(ANNELIDA, OLIGOCHAETA)

The two terrestrial enchytraeids Enchytraeus variatus and E. crypticus are true biospecies, which usually cannot be crossed in laboratory cu ltures. Although they are indistinguishable by light microscopy and ha rd to tell apart by electron microscopy (TEM of sperm), biochemically they are distinguishable at three monomorphic allozymes of 20 enzyme s ystems. The random amplified polymorphic DNA (RAPD)-PCR technique, emp loying 15 different random oligonucleotide primers, confirms an unequi vocal but small genetic separation. Comparison of 199 DNA fragments ra nging in length from 260 to 1800 bp revealed 15% polymorphism for E. c rypticus and 19% for E. variatus. They have 79 monomorphic DNA fragmen ts in common and are separated by 26 fragments. Cluster analyses consi stently assigned single individuals to the appropriate species. The ge netic distance found by RAPD analysis (Nei and Li, 1979) is only 0.17, a relatively small value for species. (C) 1998 Elsevier Science Ltd. All rights reserved.