Neandertal protein is sequenced

An international team led by researchers at WUSTL and at the Department of Human Evolution of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have extracted and sequenced a 75,000-year-old protein from a Neandertal found in Shanidar Cave in Iraq.

This is the oldest human protein ever sequenced.

Erik Trinkaus
Erik Trinkaus

“This research opens up the possibility of getting detailed protein information from past human populations, to make inferences about the evolution of human diet and physiology,” said Erik Trinkaus, Ph.D., the Mary Tileston Hemenway Professor of Physical Anthropology in Arts & Sciences.

Trinkaus is considered by many to be the world’s most influential scholar of Neandertal biology and evolution. He conducted extensive fieldwork at Shanidar Cave and is one of the authors of a paper published in the Proceedings of the National Academy of Sciences.

It is rare to recover a protein of this age and remarkable to be able to determine its amino acid sequence.

Protein sequences may be used in a similar way to DNA — to provide information on the genetic relationships between extinct and living species. As ancient DNA rarely survives, this new method opens the possibility of determining these relationships in much older fossils that no longer contain DNA.

The research presents the sequence for the bone protein osteocalcin from the Neandertal as well as osteocalcin sequences from living primates (humans, chimpanzees, gorillas and orangutans).

The team found that the Neandertal sequence was the same as modern humans.

The team also found a marked difference in the sequences of Neandertals, humans, chimpanzees and orangutans from the sequences of gorillas and most other mammals.

This sequence difference is located where the amino acid hydroxyproline is replaced by proline.

The authors suggest that this is a dietary response, as the formation of hydroxyproline requires vitamin C, which is ample in the diets of herbivores like gorillas, but may be absent from the diets of omnivorous primates such as humans and Neandertals, orangutans and chimpanzees.

Therefore, the ability to form proteins without the presence of vitamin C may have been an advantage to these primates if this nutrient was missing from their diets regularly.

This research opens the exciting possibility of extracting and sequencing protein from other fossils, including earlier humans, as a means of determining the relationships between extinct and living species, and to better understand phylogenetic relationships.