Neighboring base composition and transversion/transition bias in a comparison of rice and maize chloroplast noncoding regions.

摘要: Abstract The correspondence between the transversion/transition ratio and neighboring base composition in chloroplast DNA is examined. For 18 noncoding regions of genome, alignments rice (Oryza sativa) maize (Zea mays) were generated by two different methods. Difficulties aligning are discussed, analyzed a manner that reduces alignment artifacts. Sequence divergence < 10%, so multiple substitutions at site assumed to be rare. Observed with respect A+T content immediately flanking bases. It shown as this increases, proportion transversions also increases. When both 5'- 3'-flanking nucleotides G or C (A+T 0), only 25% observed transversions. However, when A T 2), 57% Therefore, influence on substitutions, previously reported for single region, general feature genome.