Metaphase chromosomes and karyotypes of scallop hybrids. A1, A2, D1, D2 C. farreri × P. yessoensis B1, B2, E1, E2 C. farreri × A. irradians C1, C2, F1, F2 C. farreri × M. nobilis A1, A2, B1, B2, C1, C2 the chromosomes originating from C. farreri were painted in yellow-green using the labeled genomic DNA probes from C. farreri D1, D2 - the chromosomes originating from P. yessoensis were painted in yellow-green using the labeled genomic DNA probes from P. yessoensis. Nucleolus organizer regions (NORs) in P. yessoensis were marked with arrows in (D1). E1, E2 the chromosomes originating from A. irradians were painted in yellow-green using the labeled genomic DNA probes from A. irradians. F1, F2 the chromosomes originating from M. nobilis were painted in yellow-green using the labeled genomic DNA probes from M. nobilis. Scale bars: 5µm.