Nuclear DNA content variation in the diploid-polyploid Leuciscus alburnoides complex (Teleostei, Cyprinidae) assessed by flow cytometry

The nuclear DNA content of 145 fish from the hybridogenetic diploid-polyplo id complex Leuciscus alburnoides, collected in two Iberian basins, Tejo and Guadiana was determined in erythrocytes by flow cytometry. Mean DNA conten ts for each ploidy level were compared, considering males and females of ea ch basin separately. Variations in DNA content both within and among popula tions were not significant. The diploids and triploids of both basins prese nt very small variations in genome size, respectively 2.46 +/- 0.044 pg.cel l(-1) and 3.6 +/- 0.043 pg.cell(-1). The tetraploids, found in Tejo basin o nly,had a mean value of 4.81 +/- 0.037 pg.cell(-1). No ploidy mosaicism was detected in any fish of this cyprinid complex, which may reflect an older relative age if compared with the North American complex Phoxinus eos-neoga eus.