At the end of the last ice age 10,000 years ago, a period of dramatic climate change coincided with the extinction of many large mammals. Depending on location, terminal Pleistocene extinctions were caused by some combination of rapid climatic change and over-hunting by humans. In the Arctic, where few humans lived 10,000 years ago, climatic change was probably the major culprit. Understanding phylogeographic patterns and aspects of population dynamics of species during this time of change can lead to insights of responses of species to climate change. Analysis of DNA from long-dead animals can be used to answer questions about changes in genetic patterns in relation to climate change during the late Pleistocene. These questions, unapproachable only a decade ago, now can be addressed using new techniques of DNA analysis applied to ancient bones preserved in permafrost. Recent studies of ancient DNA from late Pleistocene brown bears (Ursus arctos) suggest their genetic history is more complicated than that implied by the fossil record. This project is a pilot study to investigate patterns of genetic change in an herbivore that survived the terminal Pleistocene extinctions in northern North America and continues to inhabit the Arctic.
The study species is the muskox (Ovibos moschatus), for which there is an extensive collection of carbon-14 dated bones recently collected from permafrost in northern Alaska. Modern muskoxen have extremely low levels of genetic variability, and this pilot project will investigate whether there is sufficient variability in the ancient muskox bones to provide information on phylogeographic patterns and population genetics during the late Pleistocene and how any genetic changes might relate to climate change. Fragments of mitochondrial DNA from bones of ages spanning 5,000 to 40,000 years will be amplified and sequenced using accepted ancient DNA techniques. Replications of all stages of analysis of some bones will be performed at the University of California Los Angeles. The DNA sequences will be analyzed to determine if they can be used to infer population level parameters of genetics. Changes in genetic patterns will be compared to the paleoclimate record based on Greenland ice core records and other, more local paleo-environmental data from the North Slope of Alaska.
Though this project is exploratory, and risky, if the field and laboratory methodologies are successful, this eork should lead to valuable advances in understanding paleo- population genetics and the influence of climate change on genetic changes. This understanding could benefit the field of conservation genetics and management of endangered species.
