MON863 maize was genetically modified, using particle acceleration technology, to provide protection against certain coleopteran pests, principally corn rootworm. The genetic modification involved the transfer of the following bacterial genes:

• the cry3Bb1 gene from Bacillus thuringiensis subspecies kumamotoensis, which expresses an insect-specific protein toxin called Cry3Bb1 (a Bt-toxin); and

• the nptII gene from Escherichia coli, expressing the enzyme neomycin phosphotransferase II (NPTII) which confers resistance to particular aminoglycoside antibiotics.

Detailed molecular analysis indicates that a single copy of the ZMIR13L fragment, containing the cry3Bb1 and nptII gene cassettes, has been inserted at a single genomic locus in MON863 maize.

Both genes are intact, although during the transformation process, a small mutation occurred in the coding sequence of the cry3Bb1 gene, resulting in a single amino acid substitution in the expressed protein. The plant expressed Cry3Bb1 variant protein will therefore contain an arginine residue at amino acid position 349, instead of a glutamine residue.