MATERNAL ANCESTRY OF THE RUTILUS ALBURNOIDES COMPLEX (TELEOSTEI, CYPRINIDAE) AS DETERMINED BY ANALYSIS OF CYTOCHROME-B SEQUENCES

Cytochrome b (cyt b) sequences from specimens of the Rutilus alburnoid es unisexual complex and five bisexual species were compared to examin e hypotheses regarding the origin and maternal ancestry of this comple x. Phylogenetic analysis revealed a monophyletic relationship among un isexuals and Leuciscus pyrenaicus, clearly identifying this species as the maternal ancestor. Considerable mtDNA diversity exists among R. a lburnoides populations, with many localities exhibiting unique haploty pes. The topology recovered from analysis of cyt b variation among pop ulations suggested that R. alburnoides is polyphyletically derived fro m their sympatric L. pyrenaicus populations, indicating that unisexual lineages have been generated through multiple hybridization events. A lthough much less abundant, R. alburnoides is present outside the rang e of L. pyrenaicus suggesting that it mag have dispersed from the Tejo drainage into the northern basins. In this region, Leuciscus carolite rtii is most likely the sexual host for the unisexual complex.