Proteins in Prehistoric Skeletons Unlock the Secrets of Mankind’s Family Tree, Provides Insight Into Human Evolution

Most of what we know about the origin of mankind comes from the study of human fossils. Recently, experts have focused on the role of protein in acquiring more knowledge about humankind's family tree.

Harnessing the Power of Protein

An expanding research field called paleoproteomics studies the genetic links of humans to our long-extinct relatives. It involves the analysis of proteins in ancient materials to gain insights beyond the bounds of DNA investigation.

At the University of Copenhagen in Denmark, a team of scientists led by Dr. Enrico Cappellini is advancing paleoproteomics research into the evolution of hominids. Their study is conducted under the BACKWARD project, which runs for five years until the end of 2026.

Last July 3, Cappellini and his team revealed the oldest genetic data they collected from a hominin, a narrower category that includes species regarded as direct ancestors of humans. The information was obtained from a distant human relative who lived in Africa two million years ago. The proteins were extracted from the enamel of four teeth discovered in a cave near Johannesburg in South Africa.

In 2019, Cappellini worked with human evolution expert Dr. Frido Welker on a project that involved significant protein removal from an extinct large-age species called Gigantopithecus blacki. Proteins were extracted from a 1.9-million-year-old molar found in a cave in southern China.

Despite roaming the forested areas of Southeast Asia, the evolutionary relationship of Gigantopithecus blacki with other Great Ape species remains unclear. Through the protein sequences discovered by Welker and Cappellini, it was suggested that the Gigantopithecus group was closely related to orangutans with a common ancestor who lived from around 10-12 million years ago.

Another breakthrough in this study is the revelation that proteomes as old as two million years can be retrieved from samples preserved in tropical environments. This opened the possibility of extending biomolecular research in hominid and hominin evolution far beyond the limitations of DNA analysis.

The researchers believe that if paleoproteomics can unveil the secrets of ancient humans, then a great deal more can be learned about their evolutionary relationships. It can also offer better insights on how they spread from Africa across the globe and got associated with activities in the archeological record like fire making. As a result, it can lead to a better understanding of humankind's ancient history.

Role of Proteins in Paleoproteomics

While DNA carries genetic information, proteins work by expressing that genetic information. This means that scientists can reverse-engineer the amino acid sequence of a protein to gain information on the DNA.

Compared with DNA, proteins can survive for much longer. They can withstand a range of environmental conditions, from temperate to tropical. This longevity is vital because researchers need to look at the Middle Pleistocene period between 777,000 and 126,000 years ago to learn more about the historical lineage of the human species.

Very little DNA preservation is available from the Middle Pleistocene, so proteins are a potential molecular solution to get the needed genetic information.