Figure 4.

Sequence analysis of products of nonenzymatic primer-extension. (a) Top: Primer-extension was carried out on 2.0 μM template T9 (AGAGAG) in the presence of 40 mM 2-MeImpC and 50 mM 2-MeImpU* (U* = U, s²U, or s²T) on ice for 7 days. Bottom: Products were sequenced, and the sequence reads binned according to the number of nucleotides added to the primer; Y = C or U*. Reaction conditions: 2.0 μM primer P2, 200 mM HEPES pH 7.0, 100 mM MgCl₂. (b) Top: Primer-extension was carried out on 2.0 μM template T5 (UC₅), T6 (s²UC₅), or T7 (s²TC₅) in the presence of 40 mM 2-MeImpG and 50 mM 2-MeImpA on ice for 7 days. Bottom: Products were sequenced and the sequence reads binned according to the number of nucleotides added to the primer; R = A or G.