Cockburn A F, Newkirk M J, Firtel R A
Cell. 1976 Dec;9(4 Pt 1):605-13. doi: 10.1016/0092-8674(76)90043-x.
Most of the Dictyostelium ribosomal nontranscribed spacer DNA has been mapped using Eco R1, Hind III, and Sal I restriction digests and recombinant plasmids containing parts of the rDNA (ribosomal DNA). The repeat units are at least 42 kb (1 kilobase = 1000 base pairs = 1 kb) long; of this, 8 kb codes for the 36S rRNA precursor. The repeat units give a homogeneous pattern of Sal I, Eco R1, and Hind III restriction fragments. The repeats could be linked by a heterogeneous region in the nontranscribed spacer, not tandemly repeated, or linked in a more complicated structural arrangement. The total rDNA comprises at least 18% of the nuclear DNA.
大多数盘基网柄菌核糖体非转录间隔区DNA已通过Eco R1、Hind III和Sal I限制性酶切以及含有部分rDNA（核糖体DNA）的重组质粒进行了图谱绘制。重复单元长度至少为42 kb（1千碱基 = 1000个碱基对 = 1 kb）；其中，8 kb编码36S rRNA前体。重复单元产生Sal I、Eco R1和Hind III限制性片段的均匀模式。这些重复序列可能通过非转录间隔区中的异质区域相连，并非串联重复，或者以更复杂的结构排列相连。总的rDNA至少占核DNA的18%。
