Résumé
Gene expression studies have been tremendously changed by DNA arrays technology. Based on the sentence « same profil, same function », severals algorithms have been developped such as partioning or hierarchical clustering. However, genes are taken as a whole. In this paper, genes are sorted by their cellular gene function, giving two classes of genes (known and putatives). Thus, frequent items are searched in the neighbourhood of each unknown genes, and gives clues about their hypothetical functions. As a first step towards, a first experiment with energetical items on Plasmodium Falciparum (Malaria's agent) identify a new function to a nucleosid transporter, expressed in the early stage of infection.