Emulsion PCR amplification of ancient DNA extracts. (A) PAGE gel electrophoresis of ancient DNA extracts pre- (−) and post-amplification (+), using GS20 or Illumina adapters. Each pre-amplification lane contains 1 ng of ancient DNA. Each post-amplification lane contains one-fifth the amplification product from 1 ng (* = 0.1 ng, Wolf, right-hand lane) of starting DNA; 100-bp DNA ladder is shown for size comparison. The lengths of GS20 adapters (88 bp) and Illumina adapters (90 bp) must be taken into consideration when calculating amplified fragment size range. (B) Emulsion PCR (em) and aqueous nonemulsion PCR (aq) amplification of ancient wolf DNA. Nonemulsion PCR consistently results in higher molecular weight products, presumably due to chimeric sequences formed during the amplification process.
