Malaria transfection: a new tool to study molecular function-reply.

R. Sinden comments in this issue on the limitations of gene targeting as a tool to study malaria parasites. Gene targeting, like any other tool, certainly has limitations. In the best situation, ie. when a mutant defective phenotype can be reverted to the wild-type phenotype by gene complementation, then it can be ascertained that the observed phenotype is a direct consequence of the lack of the targeted gene product. It is thus incorrect to state that knockout studies are simply an indirect method to analyse gene function, or that in most studies the phenotype observed is not a direct consequence of the genetic modification. Perhaps what was meant is that genetic studies do not pinpoint the exact function of the gene product in the completion of the phenotype. Obviously, this requires analysis of the protein itself. We certainly accept the fact that understanding the precise function of a protein is simply beyond the reach of genetics alone.