Study Decodes Gibbon Genome, Unlocking Clues to Human Evolution

Hyderabad: Researchers have decoded the genome of gibbons, a small ape species, providing crucial insights into the evolution of humans and other primates.

The international research team, which included CSIR-Centre for Cellular and Molecular Biology (CCMB), discovered that gibbons possess a highly rearranged genome structure, far more dynamic than that of humans, chimpanzees, or gorillas.

The study, which was published in ‘Cell’, a research publication, suggested that these frequent chromosomal changes may have accelerated the species’ evolution and helped them adapt to diverse forest environments.

Gibbons, distinguished by their long arms, are found in the forests of northeast India, Bangladesh, southeast Asia and Indonesia. They can swing between branches up to 15 metres apart, at speeds of about 55 kmph, making gibbons the fast of tree-dwelling non-flying mammals.

Using advanced whole-genome sequencing and comparative genomics, the researchers mapped the gibbon’s DNA and found that certain gene families related to vocalisation, limb development, and brain function show significant differences compared to humans.

Lead scientists noted that the genome instability observed in gibbons is linked to a genetic element unique to the species, which reshuffles chromosomes during reproduction. This finding provides new insight into how primates diverged over millions of years and also has implications for understanding human genetic disorders associated with chromosomal rearrangements.

Dr Govindhaswamy Umapathy from the Laboratory for the Conservation of Endangered Species (LaCONES) at CCMB, Hyderabad, contributed genomic data and expertise in primate conservation genetics.

“The study not only places gibbons more clearly on the evolutionary tree but also provides a model for studying genomic flexibility and adaptation in mammals. The long-standing issue in the phylogeny of gibbons has now been resolved, especially because gibbons show a uniquely wide range of chromosome numbers among animals,” Dr. Umapathy told Deccan Chronicle.

He added that another long-standing question — why gibbons have unusually long limbs compared to many other primates — has been answered by identifying a 205-base-pair deletion in the SHH gene, which influences limb growth.

The study also found that the extinct gibbon ‘Junzi imperialis’, previously thought to represent a separate genus, actually belonged to the genus ‘Nomascus’. Researchers reconstructed how past climate fluctuations had shaped gibbon populations, revealing repeated cycles of decline and recovery linked to environmental changes in Southeast Asia.

The identification of the 205-bp deletion in a regulatory region of the ‘sonic hedgehog (SHH)’ gene is believed to underlie the elongated limbs of gibbons, a key adaptation for their brachiating, tree-dwelling lifestyle.