Characterization of different chromatin types in Mytilus galloprovincialis L after C-banding, fluorochrome and restriction endonuclease treatments

Abstract

In this study, we have carried out the cytogenetical characterization of Mytilus galloprovincialis L. (2n = 28) using conventional staining and banding techniques such as fluorochromes and restriction endonucleases treatment. Chromosome digestion with trypsin enzyme resulted in a G-banding pattern which allowed us to clearly identify and classify the chromosome pairs of M. galloprovincialis. C-banding and chromomycin A3 staining confirmed the existence of small amounts of constitutive heterochromatin. The treatment of samples with Alul, HaeIII, Dpn\, Mspl, HpaII and Hinfl restriction endonucleases produced specific banding patterns which demonstrate the potential of endonucleases for chromosome banding in mussels. The results obtained allow us to describe six different types of chromatin in M. galloprovincialis. The type is determined by the response of the chromosomes to the different treatments. Differential digestion by the enzyme pair Hpa\\-Msp\ of specific C-band positive heterochromatic areas in some of the chromosomes suggests the presence of méthylation. © The Genetical Society of Great Britain.