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Molecular analysis of a 11 700-year-old rodent midden from the Atacama Desert, Chile

We combined both ancient DNA and mascroscopic identification of 11,700 year old middens in the Atacama Desert, Chile to show that the past climate was much more diverse and humid in the past. Additionally, the primary rodent responsible for the midden was identified as an ancestral Phyllotis species. Notably, modern Phyllotis can only be found 100km to the north of the sampling location suggesting at least a small range shift.

Jan 01, 2002

Authors: Kuch, M., Rohland, N., Betancourt, J.L., Latorre, C., Steppan, S., and Poinar, H.

Molecular Ecology, Vol. 11, Issue 5, May 2002, pp. 913-924. DOI: https://doi.org/10.1046/j.1365-294X.2002.01492.x

DNA was extracted from an 11 700-year-old rodent midden from the Atacama Desert, Chile and the chloroplast and animal mitochondrial DNA (mtDNA) gene sequences were analysed to investigate the floral environment surrounding the midden, and the identity of the midden agent. The plant sequences, together with the macroscopic identifications, suggest the presence of 13 plant families and three orders that no longer exist today at the midden locality, and thus point to a much more diverse and humid climate 11 700 years ago. The mtDNA sequences suggest the presence of at least four different vertebrates, which have been putatively identified as a camelid (vicuna), two rodents (Phyllotis and Abrocoma), and a cardinal bird (Passeriformes). To identify the midden agent, DNA was extracted from pooled faecal pellets, three small overlapping fragments of the mitochondrial cytochrome b gene were amplified and multiple clones were sequenced. These results were analysed along with complete cytochrome b sequences for several modern Phyllotis species to place the midden sequence phylogenetically. The results identified the midden agent as belonging to an ancestral P. limatus. Today, P. limatus is not found at the midden locality but it can be found 100 km to the north, indicating at least a small range shift. The more extensive sampling of modern Phyllotis reinforces the suggestion that P. limatus is recently derived from a peripheral isolate.

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