Identification of protein residues in South African Later and Middle Stone Age materials

Overview
The processes that have led human populations of the past to develop the cultural innovations that make us different from our phylogenetically closer relatives (e.g., making composite tools, creating symbolic items, developing numerical symbol systems etc.) are the subject of intense debate. The emergence of cultural innovations implying the use of organic material (resins for hafting, poison for hunting, binders to produce paints, etc.) are highly relevant to these debates since the preparation of such compounds is often cognitively demanding and complex to transmit to new generations. We know that complex organic compounds were produced by both Middle Stone Age (MSA) populations in Africa and Neanderthals in Europe and the Near East since at least 180 ka, but evidence for these innovations remains circumstantial.
One reason for this is that finding and identifying organic compounds are particularly challenging. Ancient protein residues are degraded and mostly present in small quantities and incorporated in a complex matrix of organic and inorganic materials such as pigments, degradation products and contaminants. Analysing these types of materials requires dedicated and sensitive analytical techniques. Palaeoproteomics provides information about the taxonomy and the tissue of the organism from which the protein(s) are derived. No other technique is able to provide such information. The Palaeoproteomic research unit at the University of Copenhagen, Denmark, have already demonstrated that it is possible to extract and analyse ancient proteins from a wide variety of tissues [1–3] and dated to million years [4].
We, therefore, aim to further our understanding of the use of organic compounds in the African MSA by identifying protein residues in the inner surface of ostrich eggshells from the key site of Klipdrift Shelter (KDS), South Africa, for possible protein residues deriving from foodstuffs or beverages [5]. Additionally, we will analyse protein binder in liquefied ochre-rich mixtures contained in MSA toolkits from Blombos Cave (BBC), South Africa, considered among the first hallmarks of complex human cognition [6]. Analysing Later Stone Age (LSA) materials will add evidence to the theories relating to the route via which pastoralism was introduced to the southernmost Cape [7].