Gray P W, Hallick R B
Biochim Biophys Acta. 1979 Jan 26;561(1):53-8. doi: 10.1016/0005-2787(79)90489-1.
Euglena gracilis chloroplast DNA has an average buoyant density of 1.685 gm/cm3, corresponding to 25 mol% G . C base pairs. To test for base compositional heterogeneity within this 130 kilobase pairs (kbp) genome, previously mapped restriction endonuclease fragments were isolated, and characterized by equilibrium buoyant density centrifugation. The chloroplast DNA can be characterized as containing two major buoyant density components. A segment of 17 kbp, representing 13% of the genome and containing the rRNA genes is 43--44 mol% G . C. The remaining 113 kbp, accounting for 87% of the genome, has an average 20--21 mol% G . C content.
纤细裸藻叶绿体DNA的平均浮力密度为1.685克/立方厘米，相当于25摩尔%的G.C碱基对。为了检测这个130千碱基对（kbp）基因组内碱基组成的异质性，分离了先前定位的限制性内切酶片段，并通过平衡浮力密度离心进行表征。叶绿体DNA可被表征为包含两个主要的浮力密度成分。一个17 kbp的片段，占基因组的13%，包含rRNA基因，其G.C含量为43 - 44摩尔%。其余113 kbp，占基因组的87%，平均G.C含量为20 - 21摩尔%。
