Genetic Diversity and Evolutionary History of Great Apes

Genetic diversity among great apes reflects a complex interplay of mutation, selection and demographic shifts that has shaped the evolutionary paths of orangutans, gorillas, chimpanzees and bonobos. Comparative analyses reveal marked differences in population sizes, historical gene flow and adaptive responses to environmental pressures. Fossil-calibrated molecular clocks estimate divergence times spanning from around 15 million years ago for orangutans to less than one million years ago for chimpanzees and bonobos. Whole-genome and organelle DNA surveys have uncovered signatures of admixture, introgression from ghost lineages, and variation in the efficiency of purifying, positive and balancing selection across species. These patterns inform both fundamental questions of hominid evolution and urgent conservation strategies by identifying subspecies with low genetic variation that are especially vulnerable to habitat loss and disease. Integrating genomic, ecological and palaeontological data continues to refine our understanding of great ape history, highlighting parallel and unique trajectories that underpin their diversity and resilience.

Research from Nature Portfolio

Recent high-coverage genome sequencing of all four gorilla subspecies has revealed evidence of introgression from an extinct ‘ghost’ lineage into the ancestors of eastern gorillas, contributing up to 3% of their modern genomes. This archaic admixture event is estimated to have occurred more than 40 000 years ago and may have influenced traits such as bitter-taste perception. Complementary studies of mitochondrial diversity in critically endangered Grauer’s and mountain gorillas, using both historical museum specimens and contemporary faecal samples, have documented a severe loss of haplotype and nucleotide diversity within the past century. This decline is attributable largely to the extinction of peripheral populations, underscoring the need for targeted conservation to preserve remaining genetic variation. Together, these findings highlight the dynamic evolutionary history of gorillas and the impact of both ancient and recent events on their genetic landscapes.

Genetic Diversity and Evolutionary History of Great Apes publication trend

The graph below shows the total number of articles in genetic diversity and evolutionary history of great apes across all publications each year (not limited to Nature Index journals).

Technical terms

Admixture: The mixing of distinct ancestral populations, resulting in genomes composed of multiple lineages.

Introgression: The incorporation of genetic material from one population or species into another through hybridisation and backcrossing.

Haplotype diversity: A measure of the uniqueness of combinations of genetic variants within a population.

Effective population size: The number of individuals in a population contributing genes to subsequent generations, influencing genetic drift and selection.

Demographic history: The record of population size changes, migrations and splits over time inferred from genetic data.

Purifying selection: The selective removal of deleterious mutations, maintaining functional genetic sequences.

Balancing selection: The process by which multiple alleles are maintained in a population due to selective advantages.

References

1. Ghost admixture in eastern gorillas. Nature Ecology & Evolution (2023).
2. Significant loss of mitochondrial diversity within the last century due to extinction of peripheral populations in eastern gorillas. Scientific Reports (2018).
3. Natural Selection in the Great Apes. Molecular Biology and Evolution (2016).
4. Great ape Y Chromosome and mitochondrial DNA phylogenies reflect subspecies structure and patterns of mating and dispersal. Genome Research (2016).
5. Genetic Structure of Chimpanzee Populations. PLOS Genetics (2007).