GENETIC DIFFERENTIATION AND PHYLOGENETIC-RELATIONSHIPS AMONG GREEK CHUB LEUCISCUS-CEPHALUS L (PISCES, CYPRINIDAE) POPULATIONS AS REVEALED BY RFLP ANALYSIS OF MITOCHONDRIAL-DNA

The phylogenetic and systematic relationships among 12 populations of Greek chub (Leuciscus cephalus L.) were investigated using RFLP analys is of two PCR-amplified mtDNA segments (D-loop and cytochrome b). Thre e out of eight, and nine out of ten restriction enzymes were polymorph ic for D-loop and cytochrome b, respectively. Twenty-one different hap lotypes were detected. Estimated nucleotide sequence divergence among the 21 genotypes ranged from 0.313 to 6.79%; the mean value of sequenc e divergence among populations was 3.421 +/- 0.00%. The calculated N-S T value of 0.94, indicates high interpopulation diversity. Dendrograms based on haplotypes as well as those of populations, support the prev ious recognition of different subspecies, but these mtDNA data are not concordant with previous allozyme data among these fish. Our results suggest that to clarify phylogenetic relationships multiple genetic sy stems need to be examined. (C) 1998 Elsevier Science Ltd. All rights r eserved.