Ancient proteins may hold megafauna secrets; Ancient proteins could hold the key to unlocking the secrets of Australias lost giant megafauna, a new paper suggests. The paper highlights the work of an international team in using ancient proteins to fill in gaps of understanding that ancient DNA cannot provide, in particular the presence of diseases in ancient times. In todays Science journal, Dr Enrico Cappellini at the University of Copenhagens Centre for GeoGenetics, and colleagues argue ancient proteins can also allow researchers to look further back in time because DNA chains fall apart 10 times faster than proteins. Cappellini says proteins survive for longer simply because they are originally present in higher quantities. He says by example, in bones — one of the most common archaeological fossil materials — 20-30 per cent of the mass is represented by soft tissue, which is mainly made of proteins, in particular collagen. The team, which includes Curtin University Adjunct Professor Thomas Gilbert, says advances in high resolution, mass spectrometry technology provides the accuracy and robustness required for confident and reliable sequencing of ancient proteins. Advantages Cappellini says ancient protein has many advantages over ancient DNA in research. Ancient proteins can be recovered and sequenced even in samples in which the DNA is too quantitatively limited or too degraded to be useful, he says. Protein analysis, for example, can be useful to assign archaeological bone fragments to an certain animal species, even when these fragments are too small to be assigned on morphological basis or they come from an environment presenting harsh chemical conditions that made ancient DNA analysis impossible. Importantly he says protein expression in an organism can be tissue-, process-, and developmental phase-specific, while its genome is virtually identical over the entire lifespan of the same individual. Consequently detection of specific proteins or protein patterns in an ancient sample can allow us to identify biological processes that took place in that sample, or to identify the biological tissue of origin of a specific material of animal origin. Cappellini points to their work published earlier this year on a human medieval mouth that showed microbial proteins acting as virulence factors responsible for triggering the infection process and host proteins involved in the immune response to the infection. Using a similar approach the researchers were able to determine a 500-year-old Inca mummy had a severe bacterial infection at the time of its death.
Posted on: Fri, 21 Mar 2014 10:28:58 +0000
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