Case study: ancient sloth DNA recovered from hairs preserved in paleofeces.

Ancient hair, which has proved to be an excellent source of well-preserved ancient DNA, is often preserved in paleofeces. Here, we separate and wash hair shafts preserved in a paleofecal specimen believed to be from a Darwin's ground sloth, Mylodon darwinii. After extracting DNA from the recovered and cleaned hair using a protocol optimized for DNA extraction from keratinous substrates, we amplify 12S and 16S rDNA sequences from the DNA extract.

Mylodon darwinii DNA sequences from ancient fecal hair shafts.

Preserved hair has been increasingly used as an ancient DNA source in high throughput sequencing endeavors, and it may actually offer several advantages compared to more traditional ancient DNA substrates like bone. However, cold environments have yielded the most informative ancient hair specimens, while its preservation, and thus utility, in temperate regions is not well documented. Coprolites could represent a previously underutilized preservation substrate for hairs, which, if present therein, represent macroscopic packages of specific cells that are relatively simple to separate, clean and process.

Multilocus genotypes from Charles Darwin's finches: biodiversity lost since the voyage of the Beagle.

Genetic analysis of museum specimens offers a direct window into a past that can predate the loss of extinct forms. We genotyped 18 Galápagos finches collected by Charles Darwin and companions during the voyage of the Beagle in 1835, and 22 specimens collected in 1901. Our goals were to determine if significant genetic diversity has been lost since the Beagle voyage and to determine the genetic source of specimens for which the collection locale was not recorded.