Cytogenetic characterization of the Zebra Mussel Dreissena polymorpha (Pallas) from Miedwie Lake, Poland

Cytogenetic characterization of D. polymorpha was carried out using banding techniques such as C-banding, fluorochrome CMA3 and silver nitrate treatment. The diploid chromosome number of both investigated D. polymorpha forms (typical and albinotic) was the same 2n = 32 (NF = 56). The karyotype consisted of 5 pairs of metacentric, 7 pairs of submetacentric and four pairs of subtelo-acrocentric chromosomes. Ag-NORs were located in the telomeric position on the largest subtelo-acrocentric chromosome pair. C banding patterns indicate many sites of constitutive heterochromatin mainly located in the telomeric regions and interstitially in some chromosomes. CMA3-sites were observed in almost all chromosomes; apart from the Ag-NORs sites, they were located terminally on the chromosome arms and interstitially on three chromosome pairs. Sixteen chromosomes could be counted at the diakinesis stage of meiosis. No differences in banding chromosome patterns were found neither between both analyzed forms of D. polymorpha nor between males and females.