and as they contain several biotin-dependent carboxylases, they must have a functional biosynthetic pathway. Whether or not P. falciparum requires exogenous biotin is unknown. We used the BLAST algorithm (1) to query the latest versions of their genome sequences with the four bacterial biotin biosynthesis genes, bioF, bioA, bioD, and bioB. In C. reinhardtii, T. pseudonana, and C. merolae, we could identify genes with high sequence similarity to bioF, bioA, and bioB, but not bioD