Recent advances in the molecular genetics of Paramecium

Paramecium continues to be used to study motility, behavior, exocytosis, an d the relationship between the germ and the somatic nuclei. Recent progress in molecular genetics is described. Toward cloning genes that correspond t o mutant phenotypes, a method combining complementation with microinjected DNA and library sorting has been used successfully in cloning several novel genes crucial in membrane excitation and in trichocyst discharge. Parameci um transformation en masse has now been shown by using electroporation or b ioballistics. Gene silencing has also been discovered in Paramecium, recent ly. Some 200 Paramecium genes, full length or partial, have already been cl oned largely by homology. Generalizing the use of gene silencing and relate d reverse-genetic techniques would allow us to correlate these genes with t heir function in vivo.