DNA Mutations To Date Old Skeletons Will Help Map Human Migration History

A group of scientists has developed a new dating approach to determine the age of ancient skeletons — a method that uses the DNA of the subject and is just as accurate as the conventional radiocarbon dating.

For years, archaeologists have used radiocarbon dating as the sole way to analyze the history of ancient human skeletons and animal fossils. The technique, which involves measuring the amount of radioactive carbon in a skeleton, has proven successful on many occasions, but there are also some caveats that raise questions against it.

Essentially, when a person or animal dies, they stop exchanging carbon dioxide with the environment. The measurement of the remaining signs of radiocarbon in the skeleton provides an idea of when they died, but not always when the quantity of the extracted radiocarbon is not enough for analysis. This, combined with extra-care required for measurement, has restricted the use of the technique, raising accuracy concerns.

Many ancient remains — that could hold crucial information regarding the origin and migration history of human populations — still remain unanalyzed or incorrectly analyzed due to these issues. But, all of that may soon change because the new technique, developed by researchers from University of Sheffield in the United Kingdom, takes a different route altogether.

The idea, as the researchers described, revolves around Geographic Population Structure (GPS), an analytical model wherein scientists use a geographical record to track mutations in DNA associated with it. However, in this particular case, instead of using geographic, the researchers use mutations in DNA derived from ancient skeletons to predict how old they might be.

The technique, called Time Population Structure (TPS), is still at a nascent stage, but appropriate developments could help scientists determine the mixtures of DNA from different time periods and provide crucial insight into the ancient human migrations and cultures that shaped our world into what we see.

“The study of genetic data allows us to uncover long-lasting questions about migrations and population mixing in the past,” Umberto Esposito, one of the researchers behind the new technique, said in a statement. “Through this work, together with other projects that we are working on in the lab, we will be able to achieve a better understanding of the historical developments that took place from the beginning of the Neolithic period, with the introduction of farming practices in Europe, and throughout the Bronze and Iron Ages.”

Even in its embryonic state, the technique is providing just as accurate results as radiocarbon dating. In a recent dating test, the team analyzed 45,000-year-old samples using both methods and found a meager difference of 800 years in the results. This means the new method is good enough to be used as a primary dating method or a secondary choice to complement the findings of radiocarbon dating.

That said, it is also worth noting that the new technique could even help track the origin of modern genomes since some of the people have more ancient genomes than others or could help with the treatment of genetic disorders that are tied to ancestry and population mixing. The group is compiling additional data to further improve the time coverage scale and accuracy of the TPS model.

Esposito will present the new dating technique at the annual conference of the European Society of Human Genetics on June 18.