Nucleotide sequences of the self-splicing group-II intron of rps16 have first been determined in nine species of the Solanum genus. It was found that the observed variations in the intron length (855-864 bp) was associated with indels of 1 to 9 b. Altogether, five indels and 50 nucleotide substitutions were detected, which were used to identify six Solanum haplotypes. Although the intron sequence was in general fairly well conserved, the distribution of the described mutations among its structural elements corresponding to six preRNA domains was qualitatively and quantitatively nonuniform. The highest polymorphism levels were observed in domains I, II, and IV. The sequence of domain V was absolutely invariable, which is in agreement with its functional significance.
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