Taxonomic Structure of the Family
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Pospiviroidae |
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Genus |
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Genus |
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Presence of a central conserved region (CCR) and lack of RNA self-cleavage mediated by hammerhead ribozymes. According to the conserved residues there are basically three types of CCRs exemplified by those of Potato spindle tuber viroid (PSTVd), Apple scar skin viroid (ASSVd) and Coleus blumei viroid 1 (CbVd-1) (Fig. 2). Genera Pospiviroid, Hostuviroid and Cocadviroid share an identical subset of nucleotides within their central conserved regions which are, therefore, more closely related between them than with the CCRs of members of the genera Apscaviroid and Coleviroid (Fig. 2).
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