CLONING AND CHARACTERIZATION OF PEJERREY MITOCHONDRIAL-DNA AND ITS APPLICATION FOR RFLP ANALYSIS

Probes were cloned, characterized, and developed for all regions of th e mitochondrial DNA (mtDNA) of pejerrey Odontesthes bonariensis to pro vide the basis for the study of genetic diversity of South American at herinopsinii and to enable species identification from small amounts o f tissue. The mtDNA was extracted from liver and cleaved with Eco RI, producing four fragments (7.4, 3.4, 3.1 and 2.9 kb) which were cloned using pUC118 plasmid vectors. Sequence analysis from both ends of the fragments showed that they encode tRNA (Asp, Phe, and Ser-TGA), 12 S r RNA, cytochrome oxidase (GO) II, NADH 4, 5, and 6, and the D-loop, and that the relative positions of these genes are identical to those in the mtDNA of other teleosts. A comparison of homology with carp mtDNA nucleotide sequences revealed that tRNA (Phe and Ser-TGA) and CO II we re relatively conserved, whereas the D-loop region was highly divergen t. The cloned mtDNA probes detected mtDNA fragments from about 800 ng of total DNA extracted from liver, muscle, and single embryos of O. bo nariensis, and were effective for restriction length fragment polymorp hism (RFLP) analysis of Patagonina hatcheri, the most distant atherino psine relative of pejerrey. The cloned mtDNA probes may be useful for the analysis of genetic diversity and non-destructive species identifi cation, including the examination of eggs, larvae and juveniles. The m tDNA sequences reported here provide the basis for the design of prime rs for PCR-based RFLP analysis. (C) 1997 The Fisheries Society of the British Isles.