Summary
Species of Chilocorus differ in chromosome number owing to centric fusion of metacentric chromosomes. The concomitant loss of arms is tolerated because in all unfused chromosomes one arm is completely heterochromatic, the other euchromatic. Under the influence of colchicine, the arms of unfused and fused chromosomes contract differentially. Unless the distribution of heterochromatin is known, karyotype analysis is destined to failure.
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Dedicated to Professor H. Bauer on the occasion of his sixtieth birthday.
Contribution No. 1138, Forest Entomology and Pathology Branch, Department of Forestry, Ottawa, Canada.
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Smith, S.G. Heterochromatin, colchicine, and karyotype. Chromosoma 16, 162–165 (1965). https://doi.org/10.1007/BF00320946
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DOI: https://doi.org/10.1007/BF00320946