Genomic in situ hybridization identifies parental chromosomes in hybrid scallop (Bivalvia, Pectinoida, Pectinidae) between female Chlamys farreri and male Argopecten irradians irradians

Interspecific crossing was artificially carried out between Chlamysfarreri (Jones & Preston, 1904) ♀ and Argopectenirradiansirradians (Lamarck, 1819) ♂, two of the dominant cultivated scallop species in China. Genomic in situ hybridization (GISH) was used to examine the chromosome constitution and variation in hybrids at early embryonic stage. The number of chromosomes in 66.38% of the metaphases was 2n = 35 and the karyotype was 2n = 3 m + 5 sm + 16 st + 11 t. After GISH, two parental genomes were clearly distinguished in hybrids, most of which comprised 19 chromosomes derived from their female parent (Chlamysfarreri) and 16 chromosomes from their male parent (Argopectenirradiansirradians). Some chromosome elimination and fragmentation was also observed in the hybrids.