The genetic adaptations that chimpanzees have developed not only help them survive in the habitats they occupy, such as the jungle or savannah, but also protect them from some infections, such as malaria, according to an international study.
The study, led by University College London (UCL), included the participation of the Max Planck Institute for Evolutionary Anthropology (Leipzig), the Institute of Evolutionary Biology (IBE) in Barcelona and the University of Barcelona, among other centers in Africa, the Efe news agency reported on Thursday.
Chimpanzees, which share more than 98% of their DNA with humans, are the closest relatives, and scientists believe that these discoveries may not only shed light on the evolutionary history of humans themselves, but also on the biology of malaria infection in humans.
Furthermore, the results of this study, which suggest that climate change and land use will affect chimpanzees, could help improve conservation of these animals, which are at risk of extinction due to habitat destruction, poaching and infectious diseases.
There are only a few hundred thousand chimpanzees alive today, but they are found in very different landscapes in Africa, from dense tropical forests to open woodland and savannah.
“This makes them unique, as all other apes, apart from humans, live exclusively in forests,” explained lead author Aida Andrés, from the UCL Institute of Genetics.
“Our study shows that, in addition to acquiring behavioural adaptations, different chimpanzee populations have evolved genetic differences to survive in their different local habitats,” she added.
As chimpanzees face threats across their range, “it is important that their genetic diversity is conserved to maintain their resilience and ensure the long-term survival of this intelligent and fascinating species,” the researcher stressed.
To conduct the study, the team of researchers collected fecal samples from wild chimpanzees and, using DNA from these samples, conducted the largest study of local adaptation in endangered wild mammals to date.
The team analyzed the exomes (the part of the genome that codes for proteins) of 828 wild chimpanzees — 388 of which were included in the final analysis — from 30 different populations across the geographic and ecological range of the four chimpanzee subspecies.
By comparing the genetic information with data on the local environment in which each chimpanzee population lives, they identified genetic variants that stand out as being much more frequent in certain regions than in others and that likely confer a benefit to their carriers.
They found evidence of genetic adaptation in genes related to certain disease-causing microorganisms among chimpanzees living in forests, where there is a high concentration of pathogens (the strongest evidence was found in genes related to malaria).
This includes two genes that are also known to be responsible for adaptation and resistance to malaria in humans: GYPA and HBB, the latter responsible for sickle cell anemia in humans.
The results suggest that malaria is probably an important disease for wild chimpanzees and that adaptation to the malaria parasite occurred independently through changes in the same genes in chimpanzees and humans.
The study suggests that chimpanzees have also adapted to their savannah habitats, which have higher temperatures, less rainfall and less food availability, showing that studying savannah chimpanzees could help us understand how human ancestors adapted to similar habitats millions of years ago.
