Knowing about our ancestors from the stuff they left

DNA sequences can reveal information about an organism that no other fossil or artifacts can tell us. Specifically for humans, the genetic sequences from existing populations have revealed how those population have migrated and bred with the native populations. Even then it would always be more exciting if we could find what the genetic makeup of our ancestors was. For us it would be as close as we could in meeting them in person. We could know who they were, what special properties they had that we might have inherited, possible diseases they carried, etc. And more importantly, like we all always wonder ... from where have we come from.

 

Taken from the original paper (https://www.nature.com/articles/s41586-023-06035-2)

I would personally want to know how and where my ancestors 10, 100 or 500 generations from now have lived. Had they been living near my hometown since thousands of years? Or have they migrated from a faraway place crossing several valleys and mountains?

Some scientists from Germany and The Netherlands have just opened a way to know about our ancestors from the things that they have left behind. They have developed a way to extract the DNA of the person wearing some artifacts. Artifacts like the jewelry they ear; in this case a pendant made of deer tooth. Bones and teeth are porous and also tend to absorb bodily fluids. The bodily fluids such as sweat contains the DNA of the person. Therefore, when a person wears jewelry made of bones and teeth some, the sweat of the person can be absorbed by the jewelry. In addition to being porous, bones and teeth also contain hydroxyapatite which adsorbs DNA and protects it from degradation. DNA trapped here can potentially last for thousands of year. This brings us back to what these scientists have achieved in the paper published in Nature, which was graciously made publicly available. 

The researchers essentially developed a method by which we can extract DNA from ancient bones. In summary, the method consists of soaking the material in phosphate buffer and detergent at different temperatures. To read about the original paper in which they describe this method, you can click here.

In the latest study, they scientists used six artifacts of similar size and tried to see what DNA they could extract from them. From, one of the artifacts, a pendant made from deer tooth, they were able extract human DNA. As simple as it may sound but it consists of several intricate steps such as library preparation, enrichment and sequencing and requires a lot of hard work. 

After analysis of the DNA sequence and from the location where the tooth pendant was found, the probable wearer of the pendant was a female who lived around 18.5 thousand years ago near Denisova cave which now is in Siberia, Russia. Interesting the closest existing relative to the woman are Native Americans. The DNA sequenced matched more closely to an older population of humans (now termed as Ancient North Eurasians) that were living around the same time further east in Siberia. It also gives an insight how humans had migrated toward the American continent via the Siberia.