The family tree of humans, once so simple is now a tangled shrub, as more and more fossils add layer upon layer of complexity to what is arguably the most fundamental of questions: where did we come from? Although the adoption of transformative experimental methods has repeatedly propelled the advancement of palaeoanthropological research, genetics can be arguably considered the single approach that, in the last decades, provided the most impressive results. Specifically, high-throughput ancient DNA (aDNA) sequencing has been central to dramatically advance our understanding of human evolution, migration, and admixture after the divergence of modern humans from archaic ones in the Middle Pleistocene. However, no aDNA data have so far been recovered from hominid remains older than ~0.4 million years (Ma), due to the irreversible chemical degradation of ancient DNA.
In stark contrast, ancient proteins represent a more durable source of genetic information, reported to survive up to ~2 Ma, in hominid dental enamel, even from sub-tropical regions. Their sequences can be reliably used to confidently reconstruct the evolutionary relationships between extant and extinct species, or to determine the biological species and the sex of the organisms the fossil teeth originate from. Ultimately, mass spectrometry (MS)-based ancient protein sequencing, i.e. palaeoproteomics, already convincingly demonstrated its transformative value, currently being the only approach enabling molecular-based evolutionary reconstructions for species that went extinct millions of years ago. BACKWARD addresses major unsettled debates about African and Asian extinct hominid phylogeny, by developing and deploying a new generation of palaeoproteomic workflows, relying on the most advanced mass spectrometry and bioinformatic solutions currently available. In particular, BACKWARD aims to define the phylogenetic position of a set of extinct hominids, dated up to ~2 million years and including (i) Homo naledi, Homo erectus, Paranthropus robustus, Australopithecus africanus and Australopithecus sediba, from South Africa, and (ii) Homo erectus, Meganthropus palaojavanicus, Sivapithecus spp., and Lufengpithecus spp. from Eurasia. BACKWARD also aims to screen large sets of morphologically non-informative isolated fossil fragments of bones and teeth, to identify the species and sex of the organism from which they originated. Deciphering the evolutionary history of our own species, has always represented an inspirational target for the broad audience globally. BACKWARD’s discoveries will be shared internationally with the largest possible audience using the web and social media, public outreach events focused on different target categories based both in the EU and in the extra-EU countries from which the fossil specimens originate.
