Satellite DNA in Constitutive Heterochromatin of the Guinea Pig

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Science  10 Apr 1970:
Vol. 168, Issue 3928, pp. 263-265
DOI: 10.1126/science.168.3928.263


Total DNA and DNA from the heterochromatin and euchromatin fractions of male guinea pig liver nuclei were analyzed by cesium sulfate-silver density-gradient centrifugation. Total DNA is composed of three components: a heavy satellite DNA, a main DNA of intermediate density, and a light satellite DNA. Heterochromatin DNA shows a fourfold enrichment in the satellite components while euchromatin DNA is relatively devoid of them. The strands of both satellite DNA's are separable by centrifugation in alkaline cesium chloride. Base analyses on the separate strands demonstrate that the two satellite DNA's represent different species.