New research reveals genetic diversity and malaria resistance in wild chimpanzees
Wild chimpanzees inhabit a variety of environments in Africa, from dense tropical rainforests to more open woodland and savannah areas. According to new research, these close relatives of humans have developed intriguing genetic adaptations tailored to their habitats, including to pathogens like malaria.
Researchers analyzed genetic data from 388 wild chimpanzees in 18 countries, documenting adaptations driven by the nature of their environment and revealing previously unknown genetic diversity shaped by local conditions.
Forest environments, more so than open habitats, are rife with pathogens such as the mosquito-borne parasitic disease malaria. The study found that forest-dwelling chimpanzees showed changes in genes associated with disease resistance, including some of the same genes tied to malaria adaptation in humans.
“In forest chimpanzees, we identify signatures of adaptation to pathogens, with the strongest signal being malaria. We identify signatures of adaptation in two genes known to mediate resistance and adaptation to malaria in humans. This may represent parallel adaptation to the malaria parasite in both species,” said Aida Andrés, an evolutionary geneticist at University College London, who led the study published this week.
“This is an evolutionary study, so whether genetic variation in these two genes indeed confers resistance to malaria in the wild has not yet been established and will need to be explored in future studies. On the other hand, we found no evidence of genetic adaptation to malaria in woodland-savannah chimpanzees, perhaps due to the stronger malaria pressure associated with forest environments,” Andrés said.
Malaria remains a deadly threat to humans, with the World Health Organization estimating 597,000 malaria-related deaths globally in 2023.
Chimpanzees and their close relatives, bonobos, are the species most genetically similar to humans, sharing about 98.8% of our DNA. The human and chimpanzee evolutionary lineages diverged approximately 6.9 to 9 million years ago, according to research published in 2023.
“If, as we propose, the adaptive mechanisms to the same infectious agent are likely similar across species, identifying signatures of genetic adaptation in apes may help us identify potential yet-unknown genetic adaptations in human populations,” Andrés added.
The researchers based their findings on genetic material extracted from chimpanzee feces collected across equatorial Africa. The 52 collection sites spanned countries including the Central African Republic, Cameroon, Congo, Democratic Republic of Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Nigeria, Rwanda, Senegal, Sierra Leone, Tanzania, and Uganda.
Chimpanzees are considered endangered due to habitat destruction, poaching, and infectious diseases. The total population in the wild is estimated to range from 170,000 to 300,000, according to the World Wildlife Fund.
The study’s findings have implications for the conservation of the species, suggesting that changes in climate and land use in their range will have varying effects on different chimpanzee populations.
“While rainforest degradation is perhaps a danger mostly for forest chimpanzees, habitat changes that increase malaria pressure may be a bigger threat to woodland-savannah populations,” Andrés said.
“This study suggests that we should aim to conserve the considerable genetic diversity of chimpanzees, including their adaptive genetic diversity, to preserve existing populations and the adaptive potential of the species so they can better adapt to upcoming habitat changes due to climate change.”
