Scientists help fight chimpanzee trafficking by studying their DNA

This genomic catalog, which includes 828 individuals, can be used to link kidnapped chimpanzees -- or their meat and limbs -- to their original home, with an accuracy of 100 kilometers, which could help law enforcement fighting against poaching.

These results were published Wednesday in the scientific journal Cell Genomics.

"If we can know the genetic diversity of these endangered species and the history of their past demography, it can help us put in place better conservation strategies," the study's lead author told AFP. , Claudia Fontsere, from the Spanish Institute of Evolutionary Biology.

DNA samples have been collected from thousands of chimpanzee feces, in a program spanning 48 locations across West and Central Africa.

Feces are very useful for studying endangered species because they allow you to collect a lot of information while interfering with the animals as little as possible.

But they also come with technical challenges, as they contain little DNA from their owner.

To overcome this obstacle, the researchers used a new DNA sequencing technique, called "target capture", which was first used to study the remains of Neanderthals, damaged because they are thousands of years old. years.

This technique allowed them to discover 50% more variants of a specific chromosome (chromosome 21) compared to what had been identified so far.

Thanks to this, they were able to deduce the genetic history of the different populations of chimpanzees, considerably improving scientific knowledge in this field.

In the past, only 59 whole chimpanzee genomes had been sequenced, mostly from animals in captivity, providing little information about their origin.

Complex migrations

Like humans, chimpanzees have a complex migratory history.

Scientists here have been able to go back as far as 100,000 years ago.

"There has been a lot of debate about whether the four chimpanzee subspecies really diverge from each other or if they have genetic continuity," one of the study's authors, Mimi Arandjelovic, told AFP. from the Max Planck Institute for Evolutionary Anthropology.

“We were able to show, using different methods analyzing very old and more recent variations, that their history is complex, just like ours,” she added.

It appears that chimpanzee subspecies have been separated in the past, but have also had periods of genetic exchange -- which helps explain why previous studies have often come to different conclusions.

The researchers observed that geographical barriers between subspecies or certain populations (lakes, rivers, etc.) resulted in genetic differences.

They also learned more about interbreeding with bonobos.

An important point: strong connections have been identified between chimpanzees living in West Africa, showing that it is crucial to preserve the bridges between forests in this region, underlined Mimi Arandjelovic.

This new map could also make it possible to identify where the illegally captured chimpanzees come from.

Although reintroducing them into the wild is a difficult task due to the complex social structures within these groups of animals, individuals have been shown to fare better when released near their place of origin. .

"This can help law enforcement trace their likely route," Claudia Fontsere explained.

In the future, scientists hope to further improve this map by collecting new samples, and to extend this analysis technique to other primates.

© 2022 AFP