Patent ID: 7595177

Claim:
A method of assaying a Brassica plant for imidazolinone herbicide tolerance conferred by the PM1 mutation of the B. napus AHAS1 gene, the method comprising the steps of: a) isolating genomic DNA from the plant; b) selectively amplifying an AHAS1 gene from the genomic DNA using an AHAS1 forward primer having the sequence as set forth in nucleotides 1 to 22 of SEQ ID NO:9 and an AHAS1 reverse primer in a first amplification step, thereby producing an AHAS1 reaction mixture; c) removing the AHAS1 primers from the AHAS1 reaction mixture to produce a purified AHAS1 reaction mixture; d) in a second amplification step, further amplifying a portion of the amplified AHAS1 gene containing the site of the PM1 mutation, by combining the purified AHAS1 reaction mixture with a PM1 forward primer and a PM1 reverse primer, wherein the PM1 forward primer and the PM1 reverse primer bind to sites nested within the amplifies portion of the AHAS1 gene; e) denaturing the product of the second amplification step to produce single stranded polynucleotides that are allowed to adopt unique conformations by intramolecular interactions; and f) detecting the presence or absence of the PM1 mutation on the basis of the mobility of said single stranded polynucleotide conformers in a substrate.