HETEROCHROMATIN DISTRIBUTION AND STRUCTURE IN GYMNOTHORAX UNICOLOR (ANGUILLIFORMES, MURAENIDAE)

Mitotic chromosomes of the moray eel, Gymnothorax unicolor, were diges ted in situ with AluI, HaeIII, MboI and DdeI restriction endonucleases , and the results were compared with those obtained in the other Medit erranean species of the same family, Muraena helena. Thanks to restric tion endonuclease- (RE-) banding technique, it is possible to study th e distribution and structure of heterochromatic regions, since subsets of constitutive heterochromatin sensitive/resistant to nuclease actio n can be observed. From an analysis of the banding patterns it was pos sible to study the karyotypic structural changes between the two speci es.