caa a22 4500 477133533 CHVBK 20180405111711.0 cr unu---uuuuu 170330e19971201xx s 000 0 eng 10.1023/A:1003117200129 doi (NATIONALLICENCE)springer-10.1023/A:1003117200129 Occasional loss of expression of phosphinothricin tolerance in sexual offspring of transgenic oilseed rape (Brassica napus L.) [Elektronische Daten] [Peter Metz, Evert Jacobsen, Willem Stiekema] The commercial and economic value of genetically modified crops is determined by a predictable, consistent and stable transmission and expression of the transgenes in successive generations. No gene inactivation is expected after selfings or crosses with non-transformed plants of homozygous transgenic oilseed rape plants if the expression of the transgene in homozygous or hemizygous nature in such plants is stable. The segregation ratios of phosphinothricin (PPT) tolerance in successive generations of selfings and mutual crosses of a few independent transgenic PPT-tolerant oilseed rape plants indicated a dominant, monogenic inheritance. In within-variety and between-variety crosses no transgene inactivation was observed. However, after selfings and backcrosses with non-transgenic oilseed rape infrequent loss of the expression of the PPT tolerance transgene was observed independent from its homozygous or hemizygous nature. Molecular analysis of PPT-susceptible plants showed that the loss of expression was due to gene inactivation and not to the absence of the transgene. Methylation and co-suppression are mechanisms that might cause reduced or even loss of expression of the transgene in later generations. The implications of this observation for seed multiplication of varieties and breeding activities with transgenic oilseed rape are discussed. Kluwer Academic Publishers, 1997 biosafety nationallicence gene inactivation nationallicence phosphinothricin tolerance gene nationallicence transgenic Brassica napus nationallicence Metz Peter DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Department of Molecular Biology, P.O. Box 16, 6700 AA, Wageningen, The Netherlands aut Jacobsen Evert Graduate School of Experimental Plant Sciences, Department of Plant Breeding, Wageningen Agricultural University, Lawickse Allee 166, 6709 DB, Wageningen, The Netherlands aut Stiekema Willem DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Department of Molecular Biology, P.O. Box 16, 6700 AA, Wageningen, The Netherlands aut Euphytica Kluwer Academic Publishers 98/3(1997-12-01), 189-196 0014-2336 98:3<189 1997 98 10681 https://doi.org/10.1023/A:1003117200129 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1003117200129 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Metz Peter DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Department of Molecular Biology, P.O. Box 16, 6700 AA, Wageningen, The Netherlands aut NATIONALLICENCE 700 1- Jacobsen Evert Graduate School of Experimental Plant Sciences, Department of Plant Breeding, Wageningen Agricultural University, Lawickse Allee 166, 6709 DB, Wageningen, The Netherlands aut NATIONALLICENCE 700 1- Stiekema Willem DLO-Centre for Plant Breeding and Reproduction Research (CPRO-DLO), Department of Molecular Biology, P.O. Box 16, 6700 AA, Wageningen, The Netherlands aut NATIONALLICENCE 773 0- Euphytica Kluwer Academic Publishers 98/3(1997-12-01), 189-196 0014-2336 98:3<189 1997 98 10681 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer