A new picture of our own ancestral past has emerged through the genomic elucidation of the complex evolutionary relationships between Neanderthals, Denisovans, and modern humans. The insight that these three hominin populations exchanged genetic material through hybridization, and that this is detectable in modern humans living today, is now a central part of both scientific and societal discourse. Understanding these evolutionary processes in detail, and how they might affect the health of people living today, has become central of our understanding of ourselves. Nevertheless, how preceding hominin populations fit into their story is currently unknown. It has become clear that Pleistocene hominin populations were highly diverse. In addition to Homo erectus and Homo antecessor, they also include recently described populations such as the Denisovans, Homo floresiensis, Homo luzonensis, and Homo naledi, and previously described but elusive, and highly discussed, populations, such as Homo heidelbergensis. These hominins were present across Africa and Eurasia, with large portions of the hominin fossil record beyond the reach of ancient DNA research. It is difficult to understand the distribution in time and space of these hominin populations, and elucidate their relation to the emergence of novel hominin behaviours evident in the archaeological record, using traditional approaches.
Palaeoproteomic analysis of skeletal proteomes has recently emerged as a potential biomolecular approach across the Pleistocene, and can provide molecular evidence on hominin evolutionary relationships on a global scale. In order to fulfil the promise of palaeoproteomics on Pleistocene material, PROSPER aims to (1) characterize the variation in proteome composition within the human skeleton, (2) develop enhanced approaches to sampling skeletal remains, and (3) acquire enhanced protein recovery and analysis methods dedicated to the analysis of ancient hominin proteomes. With these insights and methods available, PROSPER aims to gain unique insights into the evolutionary relationships between Pleistocene hominins across their African and Eurasian distribution, specifically in the last one million years, for a number of hominin specimens of particular significance. This includes the emergence and dispersal of our own species, Homo sapiens.