Researchers have created the largest human ‘family tree’ ever seen

Human Population Distribution (Vones et al., Science, 2022)
Human Population Distribution (Vones et al., Science, 2022)

In June 2000, two competing researchers shook hands over the shared success of a milestone in biology: Draft presentation of the human genome.

It started with an incomplete map of our chromosomes and then blossomed into a huge mass. Individual rows It travels far and wide, over time, from all corners of the globe.

The story of humanity we shared somewhere in a sea of ​​decoded DNA.

Unfortunately, this is easier said than done. Large amounts of data, subtle differences in models, different formats and analysis techniques that prioritize different types of errors are a problem. Is an obstacle to an integrated interpretation.

Currently, researchers at the Big Data Institute (BDI) at the University of Oxford in the UK They have taken a big step by combining the forest with more than 3,600 individual views from a population of 215 into one large tree.

The branches of the tree are part of a magnificent ancestral lineage of 231 million. At its base is a proliferation of roots represented by eight very extensive ancient human genetic sequences, thousands of small pieces used to deepen our place in our past.

Three of them are Neanderthal genes, one is the Denisovan gene and a small family that lived in Siberia four thousand years ago.

“Essentially, we are rebuilding the genes of our ancestors and using them to create a series of linked evolutionary trees called the ‘sequence tree’.” Says Anthony Wilder Vones, a geneticist who led the study when he completed his PhD at PTI.

“We can estimate when and where these ancestors lived.”He adds.

His tree hierarchical system uses what is known as a concise data system, which is a computational concept that aims to represent data in an optimal amount of space. Minimize the time needed to test everything through questions.

We can use similar thinking in saving files on our own computer, zipping documents, zipping them into long folders, or saving everything on the desktop.

In this particular case, the row of a tree finds the connections between the different branches of a tree Large amounts of information can help make reading easier.

By converting data into maps with nodes representing different lineages and mapping the mutations at the margins, massive genetic databases cannot be compressed into a relatively small space. Instead, it is easily accessible through algorithms designed to search for interesting statistics.

“The strength of our approach is that it makes very few assumptions about basic data and includes both modern and ancient DNA models.” Says Vons.

By adding tags to the geographical locations of the rows, the team was able to estimate where some common ancestors may have lived and how they moved.

It reveals events we already suspect, such as how human beings migrated from Africa. Rather it suggests changes in population density within the ancestral groups we are still learning about, such as the Denisovans.

Visualization of human ancestral lineages assumed throughout time and space.Each line represents an ancestor-offspring relationship in our presumed lineage of modern and ancient genes.  The width of a line is similar to how many times the relationship is observed, and those lines are colored according to the estimated age of the ancestor.
Visualization of human ancestral lineages assumed throughout time and space.Each line represents an ancestor-offspring relationship in our presumed lineage of modern and ancient genes. The width of a line is similar to how many times the relationship is observed, and those lines are colored according to the estimated age of the ancestor.

Thanks to the efficiency of this process, there is already an impressive tree Lots of space To grow as it is More genetic data will be available in the future.

Adding millions of genes would make additional results more accurate, Accurately points out where a new line fits into a lineage that spans the globe.

This lineage allows us to see how each person’s gene sequence is related to each other at all points in the gene.Says BDI evolutionary geneticist Yan Wong.

On further consideration, there is no reason why the same approach could not be applied to other organisms. Maybe one day Earth will contribute to the global screen of life.

“Although humans are at the center of this study, this method is valid for most organisms, from orangutans to bacteria,” he said. Says Vons.

“It’s particularly useful in medical genetics, separating the real connections between genetic areas and diseases from the pseudo-links that arise from our shared ancestral history.” Concludes.

* Published in the journal Journal Science.

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