Paisley Caves Update

Faithful reader Becca H sent along a note today asking whether there had been any additional information about Paisley Caves since the original publication of the results in April 2008. Paisley Caves, you might recall, is the name of a set of rockshelters in Oregon at which were discovered human coprolites—fossilized feces—that contained mtDNA haplotypes which are associated with the founder population of Native Americans. Further, the organic material within the coprolites produced radiocarbon dates of 12,300 RCYBP, making Paisley Caves a strong candidate for a Preclovis site. Here is an update of what's been happening.

In July 2009, several letters debating the identification of mtDNA from a coprolite at Paisley caves were published in Science. All of the letters are (currently at least) open access and can be read online for free here, but in case the OA aspect goes away, here's a brief summary and links to each separate letter.

Human coprolite from Paisley Cave 5 radiocarbon dated to 12,300 BC.
Photo Credit: Photo courtesy of Dennis LeRoy Jenkins

• First, Poinar et al. argue that radiocarbon dates in the coprolite from Paisley Caves are not consistent, leading them to suggest that that is evidence that the coprolites had been contaminated
• Next, Gilbert et al. respond that the radiocarbon dates are not inconsistent, but reproducible from two independent laboratories (with one contaminated), and that although the possibility of contamination is a reality, they are not ready to change their conclusions
• Goldberg et al. argue that they examined one of the coprolites which is purportedly human and believe it is likely to be from a herbivore
• Rasmussen et al. disagree with Golberg, arguing that the specimen is indeed human, since no mtDNA from a herbivore was discovered within the coprolite, and other mammalian mtDNA did survive

Read the Full Discussion yourself here

And on September 16, 2009, the Bureau of Land Management announced it awarded funding to the University of Oregon for the continuing research at Paisley Caves. Perhaps additional excavation will clear up these lingering questions.

• University of Oregon awarded funding for archeological excavation, preservation of Paisley Caves

Paisley Caves Publishing History

The original Paisley Caves story ran in Science Express in April of 2008 and was summarized here in Paisley Caves: The Discovery of PreClovis Human DNA. The paper was formally published in Science in 2009 (see the link below).

Gilbert et al. 2008. DNA from Pre-Clovis Human Coprolites in Oregon, North America. Science 320(5877): 786-789

Thanks, Becca!