Emmons S W, Klass M R, Hirsh D
Proc Natl Acad Sci U S A. 1979 Mar;76(3):1333-7. doi: 10.1073/pnas.76.3.1333.
In order to test for the occurrence of rearrangements in DNA during development and to assess the rate of DNA divergence during evolution, we have compared restriction fragments derived from DNA from four sources: sperm cells and somatic tissues of one strain of the nematode Caenorhabditis elegans, somatic tissues of a second strain of the same species, and whole animals of a closely related species. Restriction fragments were detected by hybridizing radioactive cloned fragments to restriction digests that had been fractionated by size on agarose gels and transferred to nitrocellulose sheets. In this way, approximately 50 BamHI restriction fragments were visualized and compared. Fragments from sperm and somatic DNAs were found to be identical; 15% differed in size between the two strains. Little cross homology was found between the two species. We conclude that, if rearrangements occur in C. elegans DNA during development, they must affect fewer than a few percent of the restriction fragments or restriction sites. The difference found between the two strains and the two species is surprisingly great.
为了检测发育过程中DNA重排的发生情况，并评估进化过程中DNA的分歧率，我们比较了来自四种来源的DNA的限制性片段：一种秀丽隐杆线虫品系的精子细胞和体细胞组织、同一物种的第二种品系的体细胞组织，以及一个近缘物种的完整动物。通过将放射性克隆片段与已在琼脂糖凝胶上按大小分级并转移到硝酸纤维素膜上的限制性酶切消化产物杂交来检测限制性片段。通过这种方式，大约50个BamHI限制性片段得以可视化并进行比较。精子和体细胞DNA的片段被发现是相同的；两个品系之间15%的片段大小不同。两个物种之间几乎没有交叉同源性。我们得出结论，秀丽隐杆线虫DNA在发育过程中如果发生重排，那么受影响的限制性片段或限制性位点必定少于百分之几。两个品系和两个物种之间的差异大得出奇。
