Cambridge O Level Biology · Syllabus 5090 · Biotechnology and Genetic Modification
Gene flow
What is Gene flow?
The movement of alleles from one population into another. Where a genetically modified crop is grown, gene flow is the possibility that pollen from the crop reaches a compatible wild relative growing nearby, cross-pollination occurs, fertilisation succeeds, and offspring carry the inserted allele, so that the feature may spread into the wild population. Every step in that sequence is a condition rather than a certainty: the two plants must be able to breed together, the pollen must reach a stigma, and fertilisation must succeed. Gene flow is therefore a genuine possibility whose likelihood depends on the crop, the wild relatives present and the conditions - not an automatic consequence of growing a GM crop, and not something that happens between unrelated species in ordinary field conditions.
This definition is part of the Biotechnology and Genetic Modification chapter in Cambridge O Level Biology.