Figure 2.

SNuPE assays for H19 with control DNA templates. (a) DNA from castaneus (cas), domesticus (dom) and from castaneus × domesticus F₁ (F1) mice. Castaneous DNA incorporates dGTP and domesticus DNA incorporates dATP. F₁ DNA, representing a 1:1 mix of the castaneus and domesticus templates, incorporates both of the nucleotides. dATP incorporation in F₁ is higher than dGTP incorporation, although, theoretically, it should be equivalent (see text). The experimentally observed relative incorporation of the two nucleotides by F₁ DNA was used to derive a correction factor (see Materials and Methods) for dGTP incorporation. (b) Castaneus and domesticus DNA mixed in known proportions as indicated, amplified, and assayed by SNuPE. The expected values of A/(A+G) on the basis of relative concentrations of domesticus and castaneus DNA used in the mix are compared with those observed.