Hansen L B, Siegismund H R, Jørgensen R B
Botanical Institute, Øster Farimagsgade 2D, DK-1353 Copenhagen K, Denmark.
Heredity (Edinb). 2003 Sep;91(3):276-83. doi: 10.1038/sj.hdy.6800335.
We have earlier shown extensive introgression between oilseed rape (Brassica napus) and B. rapa in a weedy population using AFLP markers specific for the nuclear genomes. In order to describe the progress of this introgression, we examined 117 offspring from 12 maternal plants from the introgressed population with the same AFLP-markers; AFLP data were supported by chromosome counting. We also analysed the offspring with a species-specific chloroplast marker and finally evaluated the reproductive system in selected maternal plants. Our results indicated a high outcrossing rate of the introgressed maternal plants. It seemed that B. rapa most often functioned as the maternal plant in the introgression process and that the amount of oilseed rape DNA was highly diminished in the offspring compared to their introgressed maternal plants. However, our analysis of plants from the weedy population indicated that introgression can lead to both (1) exchange of chloroplast DNA between species producing B. rapa-like plants with B. napus chloroplasts and (2) incorporation of B. napus C-genome DNA into the B. rapa genome. Therefore, we question whether it can be regarded as containment to position transgenes in the chloroplast or in specific parts of the nuclear genome of B. napus.
我们之前利用针对核基因组的AFLP标记，在一个杂草种群中展示了油菜（甘蓝型油菜）和白菜型油菜之间广泛的基因渐渗。为了描述这种基因渐渗的进程，我们用相同的AFLP标记检查了来自渐渗种群中12株母本植物的117个后代；AFLP数据得到了染色体计数的支持。我们还用一个物种特异性的叶绿体标记分析了这些后代，最后评估了选定母本植物的生殖系统。我们的结果表明渐渗母本植物的异交率很高。在基因渐渗过程中，白菜型油菜似乎最常作为母本植物，并且与渐渗母本植物相比，后代中油菜的DNA量大幅减少。然而，我们对杂草种群中植物的分析表明，基因渐渗可以导致：（1）产生具有甘蓝型油菜叶绿体的白菜型油菜样植物的物种之间叶绿体DNA的交换，以及（2）甘蓝型油菜C基因组DNA整合到白菜型油菜基因组中。因此，我们质疑将转基因定位在甘蓝型油菜的叶绿体或核基因组的特定部分是否可被视为一种遏制措施。
