DNA breakthrough could unlock evolution

The world's first fossil protein sequence has been carried out, making this a major scientific breakthrough, which has the potential to bring about changes in evolutionary theory.

A team of researchers at the University of Newcastle upon Tyne in the United Kingdom, along with collaborators at Oxford, Harvard and Michigan State universities, have been able to examine the molecular structure of two bison bones more than 55,000 years old.

The research also has the potential to be applied to much older fossils to gain the most accurate information ever collected about the genetic make-up of ancient species. They are hoping that in future their approach may be able to find the answers to long-standing evolutionary puzzles, even perhaps the connection between dinosaurs and birds.

Protein sequencing enables the scientists to 'track back' the DNA of a species and involves breaking the protein down into the component amino acids.

The protein sequencing was carried out at Michigan State University using matrix-assisted laser desorption ionisation mass spectrometry (MALDI-MS), developed in part by this year's Nobel Prize (chemistry) winning scientist Koichi Tanaka. Using a variety of approaches, the protein osteocalcin from the ancient bison bone was broken apart and the information on the fragments used to construct the amino acidsequence.

Remarkably, the protein was recovered intact - supporting earlier hopes that the protein would prove stable. This has given the team renewed optimism regarding the potential for protein sequencing and extending molecular records farther back in time.

The researchers were able to sequence the bison fossil's DNA as well as its protein (the first time that DNA and protein sequences have been obtained from the same fossil) but they believe this new technique could enable them to determine the genetic make-up of much older fossils in which the more fragile DNA has broken down. However, the challenges are very great: to find out how species have evolved they need to delve back for millions of years, not thousands.

Dr Christina Nielsen-Marsh, a member of the research team, said: "Although 55,000 years sounds a long time, it is not going back far enough to tell whether a species has really evolved. We hope to go back further in time and analyse older fossils to see how species have evolved over millions of years."