Overview

Directly dating mammal fossils older than the limit of carbon dating (~50,000 years) is very challenging, and this has led to a research focus on the most recent past in forming our understanding of mammalian response to changing environments. However this narrow time window is extremely limiting if we aim to understand the effects of climate change on land-based organisms, or unpick our own evolutionary history. It has become increasingly clear that the patterns of human evolution during the last 3 million years are far more complex than previously believed. We are therefore hard-pressed to pinpoint the major evolutionary drivers for both humans and other mammals, and to compare patterns across the African continent. The key problem preventing the required comparisons is chronology.

Our project team has been developing and employing methods for dating using the breakdown of the original proteins trapped within fossils. Excitingly, we have just made a methodological breakthrough which enables amino acid (a protein breakdown product) dating to be undertaken on tooth enamel (a composite material of protein and calcium phosphate). Dating enamel has the enormous advantage of providing a direct date on mammal teeth (critical fossils of interest) and the new method now enables routine amino acid analysis, successfully dating UK material up to 3 million years in age. This technique is ready for development to a range of mammalian species and additional geographic regions, potentially revolutionising our understanding of mammalian evolution (including humans) during the last few million years, and their response to environmental change, at the local and the global scale.

This proposal will address the three areas of technology development needed for this dating method to be used routinely, but the time frame it opens up (the last ~4 million years) will enable a significant shift in the range of research questions answerable regarding the environmental forces on mammalian evolution, including that of humans. The three strands of technological advance proposed are:

1) a microfluidics (“lab-on-a-chip”) approach, which will enable both a significant decrease in the physical sample size needed, as well as preparation / analyses to be undertaken outside specialist labs;

2) combining analysis and imaging of both the organic and inorganic fractions to understand their structure, function and any impact on the protein breakdown; and

3) using advanced chemical models to understand the breakdown reactions.