Abstract:

The commercial production and extensive environmental release of genetically modified (GM) crops have aroused worldwide concerns and debates over the biosafety of these crops. Transgene escape and its potential environmental risks are among the most debated biosafety issues. Transgene(s) can move from a GM crop to its non-GM counterparts and wild relatives via pollen-mediated gene flow, potentially causing various types of environmental problems. Effective biosafety assessment and research can facilitate the safe and sustainable application of GM crops. Following the framework of risk assessment, there are two critical steps for assessing environmental risks caused by transgene escape: (1) to measure frequencies of transgene escape from a GM crop to its non-GM counterpart or wild relative species (including weedy forms) via pollen-mediated gene flow; and (2) to determine the persist and spread of escaped transgene(s) in wild or weedy populations through introgression. The study of hybridization-introgression represents one of the most important and common phenomena in plant evolutionary, the study of which also includes the two important steps: to estimate frequencies of hybridization and to know the introgression of gene(s) in question within or among populations. The evolutionary theory of hybridization-introgression has a very close relationship with research and assessment of transgene escape and its potential environmental risks. The process of hybridization-introgression usually results in speciation, endangered status, extinction, or adaptive evolution of plant species. This is because important effects such as genetic assimilation, demographic swamping, and selective sweeps during the hybridization-introgression process, can considerably affect the evolutionary process of plant populations, into which the incorporation of transgenes may complicate the evolutionary process. If transgenes in question can significantly increase the fitness of individuals, they will quickly spread in the populations through fast introgression and significantly influence population dynamics bring certain evolutionary consequences. Therefore, we recommend applying the evolutionary theory of hybridization-introgression to guide the research and assessment of potential environmental risks caused by transgene escape.

Key words: biosafety, transgene escape, ecological consequence, hybridization, introgression, evolution, fitness, risk assessment