Alternative transcription in dcr-1/1a in A.pisum , A. gossypii and R.padi . a) Representation of the C-terminal region of DCR-1, the 3’ region of dcr-1 and the transcripts sequenced for the three species. For each of them, two alternative transcripts were found for dcr-1/1a, one retaining intron 15 and another one splicing it. Only one transcript was found for A. pisum dcr-1b, with intron 15 spliced. Apidcr-1b lacks a portion of exon 15 as compared to Apidcr-1a which corresponds to a deletion of 47 aa in the middle of the RNase IIIa domain. b) Fragment of the alignment of the translated amino acid sequence of the transcripts, showing the region around intron 15. The retention of intron 15 results in an insertion of 19 aa in A. pisum DCR-1a. In A. gossypii and R.padi this retention results in premature stop codons (marked by an *) and the loss of the entire RNase IIIb domain of DCR-1.