2005 Volume 70 Issue 3 Pages 345-349
We studied chromosomal distribution of C-banded constitutive heterochromatin and nucleolus organizer regions (NORs) in four Dascyllus species with inter- and intraspecific Robertsonian polymorphism. In these results, only D. melanurus with an ancestral karyotypic feature consisting of 48 acrocentric chromosomes had characteristic C-bands in terminal regions of the long arms of NOR-bearing chromosomes and in subterminal regions of the long arms of the smallest chromosomes. The present results revealed that the karyotype of D. melanurus was ancestral-like in conventional staining but most differentiated in constitutive heterochromatin distribution. The statistical analysis showed precisely that the NOR-bearing chromosomes varied among the species but not within the species irrespective of intraspecific Robertsonian polymorphism. The present results obtained from a combination of the banded analyses and the statistical one provided useful information enabling a detailed understanding of chromosome evolution and related problems.
