Frequent Occurrence of Transgene Deletion in Transgenic Plants.

The status of the transgene in tobacco plants transformed by Agrobacteriuln was analyzed with PCR. 1\velve percent of the transgenic plants with the nptII gene showed different levels of transgene deletion, which was also found in transgenic watermelon (10-30%) and carrot (40-60%). It appeared that the percentage of transgenic plants carrying deleted trans genes depended on both the transgene and the plant. It is suggested that the transgene should be inserted between a right border and a selection marker to reduce the number of transgenic plants containing deleted trans genes after selection. [ABSTRACT FROM AUTHOR]