Abstract
Chromosomes were studied in female specimens of the ostrich, Struthio camelus L., cassowary, Casuarius casuarius (L.), emu, Dromiceius novaehollandiae (Lath.) and rhea, Rhea americana L. by means of blood and feather pulp culture techniques. Male karyotypes were also studied in the emu and rhea. The diploid chromosome number was most likely 80 in the ostrich and rhea and 82 in the emu, while the exact number could not be determined in the cassowary. Karyotypes of the 4 species were strikingly similar and apparently interchangeable with one another with slight modifications of the centromeric position in one or two pairs of macrochromosomes. No heteromorphic macrochromosomal pair was found either in female specimens or in male ones of the ratite species so far examined, except for a female rhea. This specimen was found to possess an acrocentric chromosome which was evidently a member of nos. 4–6, but considerably smaller than any other chromosome of the group. 3H-thymidine autoradiography provided no more information than the straightforward morphological analysis with regard to the differentiation of the sex-chromosomes.
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Contributions from the Chromosome Research Unit, Hokkaido University. Dedicated to Emeritus Professor Sajiro Makino on the occasion of his retirement, in honor of his 40 years' service with the University. Supported by a grant from the Scientific Research Fund of the Ministry of Education (No. 584099).
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Takagi, N., Itoh, M. & Sasaki, M. Chromosome studies in four species of Ratitae (Aves) . Chromosoma 36, 281–291 (1972). https://doi.org/10.1007/BF00283247
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DOI: https://doi.org/10.1007/BF00283247