GENOMIC PPO CLONES

The present invention relates to the isolation of genes encoding polyphenol oxidase (PPO) from plants. In a first aspect of the present invention there is provided a method for preparing nucleic acid encoding PPO , fragments and derivatives thereof, which method includes providing a sample of plant tissue, a first primer in sense orientation havi ng a sequence corresponding to a conserved region of a PPO gene, a second primer in antisense orientation having a sequence corresponding to a conserved region of a PPO gene; isolating genomic DNA from said plant tissue; and amplifying the genomic DNA using the first and second primers. Surprisingly, the applicant has found that PPO genes in plants lack introns and, therefore, fragments of PPO genes may be amplified directly from genomic DNA of a range of plants. The lack of introns means that the size of the fragments can be predicted an d bands of the appropriate size can be selected for cloning.