Johnson S A, Davidson E H, Britten R J
J Mol Evol. 1984;20(3-4):195-201. doi: 10.1007/BF02104726.
A comparison has been made between the Sp88 gene regions of the DNAs of the sea urchins Strongylocentrotus purpuratus (Sp.) and Strongylocentrotus drobachiensis (Sd.). Examination of the 3' terminal part of the transcribed region revealed a short repetitive sequence present in Sd. but absent from Sp. A 12-nucleotide sequence present once in Sp. is almost perfectly duplicated at both ends of the repeat in Sd., suggesting that a mobile repeat was inserted in the Sd. genome. Other members of this family of repeated sequences occur in many interspersed locations in the genomes of both species. Except for the insertion duplication, the inserted sequence lacks direct or reverse repeats.
对紫海胆（Sp.）和北方球海胆（Sd.）DNA中的Sp88基因区域进行了比较。对转录区域3'末端部分的检查发现，Sd.中存在一个短重复序列，而Sp.中不存在。Sp.中出现一次的12个核苷酸序列在Sd.的重复序列两端几乎完全重复，这表明一个可移动的重复序列插入到了Sd.基因组中。这个重复序列家族的其他成员出现在这两个物种基因组的许多散布位置。除了插入重复外，插入序列缺乏正向或反向重复。
