Researchers Create Atlas of Human Gene Mixing

Slavery and trade have left their marks on the genetic make-up of populations around the world. A new interactive map developed by Oxford University and University College London reveals the history of genetic mixing between populations around the world in the last 4,000 years.

The latest study found how each of the 95 populations in Europe, Africa, Asia and South America mixed with each other.

Researchers developed complex statistical method called 'Globetrotter' to analyze the DNA of 1490 people from different populations around the world. They looked at specific "chunks" of DNA that were shared by individuals living in different populations. People who have similar "chunks" of genetic material are more closely linked to each other.

The study found that 80 percent of the population showed genetic mixing, Nature reported. Some of the "gene mixing" is already known due to historical records while others aren't.

Historians believe that the Hazara people of Pakistan are descendants of Mongolian warriors. The present study not only confirmed this idea but also showed that certain populations living as far away as Turkey are also genetically linked with Mongols, according to a news release.

DNA of Kalash people living in a remote region of Pakistan also show traces of genes from Europeans. The Kalash believe that they are the descendants of Alexander the Great's army. However, there was no record backing this claim. The latest study shows that these people have genetic input from Europeans between 990 and 210 BC, Nature reported

"Many of our genetic observations match historical events, and we also see evidence of previously unrecorded genetic mixing. For example, the DNA of the Tu people in modern China suggests that in around 1200 CE, Europeans similar to modern Greeks mixed with an otherwise Chinese-like population. Plausibly, the source of this European-like DNA might be merchants travelling the nearby Silk Road," said Dr Simon Myers of Oxford University's Department of Statistics, co-senior author of the study.

"Each population has a particular genetic 'palette', said Dr Daniel Falush of the Max Planck Institute for Evolutionary Anthropology in Leipzig, co-senior author of the study.'If you were to paint the genomes of people in modern-day Maya, for example, you would use a mixed palette with colours from Spanish-like, West African and Native American DNA."

The study doesn't just help in looking at the ancestry of people, but also shows how diseases can affect populations. Some diseases are found only in certain groups of people. Also, effects of certain drugs are known to vary among populations. Understanding the role of genetics in disease spread within a population could help design new therapeutics.

The study is published in the journal Science.