Repetitive sequences of the sea urchin genome. II. Subfamily structure and evolutionary conservation.
Repetitive sequences of the sea urchin genome. II. Subfamily structure and evolutionary conservation.
复制标题
海胆基因组的重复序列。
DOI：
10.1016/0022-2836(81)90258-8
复制
发表时间：
1981
影响因子：
5.6
通讯作者：
Davidson,EH
中科院分区：
文献类型：
--
作者：
Scheller,RH;Anderson,DM;Posakony,JW;McAllister,LB;Britten,RJ;Davidson,EH
从重组λ-基因组文库中分离出三个重复序列家族的成员，并用于研究这些家族内的序列关系。其他地方的研究表明，所有三个重复序列家族的成员都是组织特异性转录的。测定了家族内异源双链的热稳定性，并通过限制性酶切图谱、异源双链可视化、凝胶印迹杂交和直接测序确定了相关序列之间的共线性程度。一个大的和非常分歧的家庭，命名为2108，被证明是由许多小的重复序列亚家族的集合。每个亚家族包括<40个成员，这些成员在基因组中不连续，但非常密切相关，长度为数千个核苷酸的共线性序列元件。不同的2108个亚家族只共享小的序列子元素，这些子元素在每个亚家族中以不同的线性顺序出现，并被不同的序列包围。由短重复序列组成的第二个趋异家族，2109家族，也包括许多内部同源的小亚家族。第三个家族，2034，内部序列差异很小，没有明显的亚家族结构。重复序列亚家族可以是生物学上重要的重复单元。因此，特定的2108个亚家族在进化上具有显着的保守性。在近2亿年前分化的海胆物种中发现了高度同源的2108个序列，尽管这些物种的单拷贝DNA序列中只有约10%的同源性足以交叉反应。
Members of three repetitive sequence families were isolated from recombinant λ-genome libraries, and were used to investigate sequence relationships within these families. Studies presented elsewhere show that members of all three repeat sequence families are transcribed tissue-specifically. The thermal stability of intrafamilial heteroduplexes was measured, and the extent of colinearity between related sequences was determined by restriction mapping, heteroduplex visualization, gel blot hybridization, and direct sequencing. One large and very divergent family, named 2108, was shown to consist of an assemblage of many small repeat sequence subfamilies. Each subfamily includes <40 members which are not contiguous in the genome but are very closely related colinear sequence elements several thousand nucleotides in length. The different 2108 subfamilies share only small sequence subelements, which in each subfamily occur in a different linear order and are surrounded by different sequences. A second divergent family consisting of short repetitive sequences, the 2109 family, includes many small internally homologous subfamilies as well. A third family, 2034, displays little internal sequence divergence and no apparent subfamily structure. The repeat sequence subfamilies may be biologically significant units of repetition. Thus specific 2108 subfamilies were shown to be evolutionary conserved to a remarkable degree. Highly homologous 2108 sequences were found shared among sea urchin species which diverged almost 200 million years ago, although only about 10% of the single copy DNA sequences of these species are now homologous enough to crossreact.