Figure 1. Illustration of rice transformation through particle bombardment. The starting explant is dry seed, which is sterilized using standard laboratory procedures and then plated on media containing an auxin (2,4D) to induce enlargement of the scutellum and formation of actively dividing cells. Approximately, 5 days later this tissue is subjected to particle bombardment, whereby transformation vectors for constitutive or tissue/organ-specific expression are introduced into the cells, together with a constitutively expressed selectable marker gene. Following transformation and a number of subcultures in the presence of the selectable marker gene (in this case the antibiotic-resistance gene, hygromycin phosphotransferase), regeneration of intact plants takes place, which can subsequently be transferred to the greenhouse for further development and seed set. Regenerated plants are analysed through a battery of molecular and biochemical tests to verify their transgenic nature, and levels and stability of expression of the introduced transgene(s). Where appropriate, biological assays are carried out on primary transformants and progeny to establish biological function, e.g. insect feeding assays to determine insect resistance, or inoculation with a virus to determine resistance to viral infection.

Figure 2. The global area of transgenic crops and the countries where they are grown. From James C (2006) Global Status of Commercialized Biotech/GM Crops: 2006. ISAAA Brief No. 35. ISAAA: Ithaca, NY.

Figure 3. Mark Newman's world map that gives each territory a size proportional to its population, a so-called ‘density-equalized’ cartogram' Webb (2006). Copyright © 2006, Nature Publishing Group.