Perucho M, Hanahan D, Wigler M
Cell. 1980 Nov;22(1 Pt 1):309-17. doi: 10.1016/0092-8674(80)90178-6.
The calcium phosphate precipitation method of Graham and van der Eb (1973) is an efficent means of introducing DNA into culturaed animal cells. Cells which incorporate one selectable marker are also likely to incorporate one selectable marker are also likely to incorporate sequences from the carrier DNA. Both selected and unselected markers are found integrated in the high molecular weight nuclear DNA of the host. In the present study, we demonstrate that exogenously acquired sequences are gentically linked, segregating and amplifying coordinately, and that their flanking sequences derive primarily from the carrier species rather than the host species. Based on these results, we propose that, upon transformation, the host cell ligates incorporated DNA into a large concatameric structure which may at times be as large as 2000 kilobases. From blotting data alone we cannot determine whether this structure is chromosomal or extrachromosomal in location.
格雷厄姆和范德伊布（1973年）的磷酸钙沉淀法是将DNA导入培养的动物细胞的一种有效方法。整合了一个选择标记的细胞也可能整合了一个选择标记，并且也可能整合来自载体DNA的序列。已选择和未选择的标记都被发现整合到宿主的高分子量核DNA中。在本研究中，我们证明外源获得的序列是基因连锁的，协同分离和扩增，并且它们的侧翼序列主要来自载体物种而非宿主物种。基于这些结果，我们提出，在转化时，宿主细胞将整合的DNA连接成一个大的串联体结构，其大小有时可能高达2000千碱基。仅从印迹数据我们无法确定该结构在位置上是染色体的还是染色体外的。
