Bone marrow chromosomes in Corvus species (Corvidae: Passeriformes: Aves).

The diploid number of 80 +/- chromosomes has been established for two species of Indian crows, viz. Corvus splendens splendens Viellot, and Corvus macrorhynchus culminatus Sykes. In addition to the usual macro- and microchromosomes, there exist certain elements in both cases, falling in between the two different size categories of chromosomes. The number of these medium-sized, and of the macrochromosomes, was found to be 6 and 14, respectively, in both species. All chromosomes included in these two categories depict the clear position of their centromeres, while in the microchromosomes the centromeric position is not distinct. The sex-chromosome mechanism which has been studied only in Corvus splendens splendens, is of the ZZ and ZW type in the male and female, respectively.