The condensation reaction of hexanucleotides 5'-pGGGCCrC, 5'-pGCGCGrC, and 5'-pGCCCGrG was investigated in the presence of water-soluble carbodiimide (WSC) and imidazole at 0 ℃. The efficiency of the condensation of hexanucleotides with WSC was investigated to know whether these hexanucleotides act as a partial template to promote the elongation reaction. The condensation reaction mainly yielded cyclic-hexanucleotides (30 - 60 %) and small amount of 12-mers (＜ 10 %), which opposed our expectation. The yield of cyclization was in the order 5'-pGGGCCrC ≅ 5'-pGCGCGrC ＞ 5'-pGCCCGrG and that of dimerization was in the order 5'-pGGGCCrC ≅ 5'-pGCGCGrC ＜ 5'-pGCCCGrG. The trend to cause efficient cyclization could be an obstacle at an early stage of chemical evolution of RNA.

　海底熱水噴出口環境を模倣した進化フローリアクターを用いて、アラニンのラセミ化を定量的に計測したところ、D-エナンチオマーの方が10%過剰となった。この反応におけるエナンチオマーの過剰率は溶液のpHにかかわらず、塩化ナトリウムに依存することが判明した。イオン強度が高くなると対掌体間偏りは減少した。この結果は、海底熱水噴出口環境においてはラセミ化反応に偏りが生ずることを強く示唆する。