SMN1 and spinal muscular atrophy: In the present study, we used a C. elegans model for Spinal Muscular Atrophy (SMA),in which smn-1, the ortholog of SMN1, has been silenced via RNAi specifically in 19 motoneurons. These animals display an age-dependent degenerationof motoneurons (MNs) detected as altered locomotion, the early disappearanceof neurons expressing the green fluorescent protein, and finally theapoptotic death of targeted neurons.