Scientists create the largest human family tree and reveal the history of our species

The largest family tree in the history of human genetic diversity reveals how individuals around the world are related and provides insight into major events in the history of mankind, their chronology and geographical location.

This new genealogical network that predicts common ancestors and retrieves key events such as human migration out of Africahas been created by a team led by the University of Oxford (United Kingdom) and the method used is published in Science.

The underlying method could have broad applications in medical research, for example identifying genetic predictors of disease risk.

“The story that generated all the genetic variation”

“We have basically built a huge family tree, a genealogy for all of humanity, that models as accurately as possible the history that generated all the genetic variation that we find in humans today,” said Yan Wong of the Big Data Institute. of the University of Oxford and one of the authors of the report.

This genealogy allows us to see, he explained, how the genetic sequence of each person is related to all the others, throughout all the points of the genome.

The study integrated data on modern and ancient human genomes from eight databases and included 3,609 individual genomic sequences from 215 populations.

Ancient genomes included samples found around the world ranging in age from 1,000 to more than 100,000 years.

Algorithms predicted where common ancestors needed to be present in evolutionary trees to explain patterns of genetic variation, and the resulting network contained almost 27 million ancestors.

Genomic data from hundreds of thousands of people

In recent decades, genomic data have been generated for hundreds of thousands of people, including prehistoric thousands, which raises the possibility of tracing the origins of genetic diversitybut the great challenge was to combine the genomic sequences from many databases and develop algorithms capable of handling the large amount of data.

The Oxford researchers used a new method that can easily combine data from multiple sources and scale to accommodate millions of genomic sequences.

Individual genomic regions are inherited only from the father or mother, so the ancestry of each point in the genome can be thought of as a tree.

“Tree Sequence”

The set of trees, known as a “tree sequence” or “ancestral recombination plot,” links genetic regions through time to the ancestors in which the genetic variation first appeared.

The lead author of the study, Anthony Wilder Wohns, explained that the genomes of our ancestors are reconstructed and used to form a vast network of relationships, after which it can be estimated when and where those ancestors lived.

The team plans to continue enriching the pedigree map with the addition of more genetic data as it becomes available.

Wong felt that this study lays the groundwork for the next generation of DNA sequencing, that allows to make increasingly precise trees until arriving at a unique and unified map that explains the descent of all the human genetic variation that exists today. (I)