The characterization of <i>Muraena Helena</i> L. mitotic chromosomes: karyotype, C-banding, nucleolar organizer regions, and in situ digestion with restriction endonucleases

Abstract

We investigated the chromosome complement of <i>Muraena Helena </i>L. using C-banding, nucleolar organizer region silver staining, and restriction endonuclease digestion. We found a diploid number identical to that previously found in other Muraenidae (2n = 42). C-banding revealed the presence of constitutive heterochromatin in the centromeres of all chromosomes as well as in most telomeres of acrocentric chromosomes. Nucleolar organizer regions were detected only on the short arm of chromosome 7. Digestion with either <i>Hae</i>III, <i>Mbo</i>I, or <i>Dde</i>I restriction endonucleases produced a clearcut, specific banding pattern for each enzyme and indicated the existence of at least two different classes of highly repetitive DNAs. The short arm of chromosome 7 varied in size and staining characteristics.