Biotech Updates

GM Papaya Transgenes Remain Stable For Several Generations

June 13, 2008

Insights from transgenic papaya genome sequences revealed that transgenes generally stay put following integration and can achieve stable expression level from generation to generation, according to a paper published by the journal Nature Biotechnology. The SunUp papaya variety, developed by scientists to combat the papaya ring spot virus, is the first transgenic organism to have its genome sequenced.

Ajay Kohli and Paul Christou, authors of the paper, noted that the genome now provides definitive evidences against transgene rearrangement, which is one of the suspected causes of the instability of inserted genes. The transgenes generally become a fixed part of the genome, with predictable and consistent expression patterns. Introduction of the foreign genes interrupted no endogenous gene; so that except for the virus resistance characteristic, the GM plants are functionally similar to their non-transformed counterparts. Despite the stability of the GM papaya variety, however, nonessential sequences such as the tetA and nptII marker genes and vector DNA remain in its genome.

Read the paper at