Long-lived corals accumulate somatic mutations under purifying selection as they age
Genomic analysis of Acropora palmata colonies reveals power-law mutation patterns mirroring human tissue aging and enables somatic genetic age estimation.
In the reef-building coral Acropora palmata, researchers tracked somatic genetic variation to understand how mutations accumulate across long lifespans. The team sequenced whole genomes from eight colonies in Curaçao at 70–100× coverage to document shifts in variant allele frequencies. They observed large numbers of somatic mutations in six- to ten-year-old colonies and used inferred mutation rates to estimate the age of another colony at nearly a century old. Somatic mutations were never fixed at polyp or branch levels, maintaining frequencies below 0.5, but their allele frequencies followed a power-law distribution resembling aging human tissues. Somatic variants showed no evidence of positive selection, operating instead under purifying selection. Additionally, profiling 28 samples along a single branch using a SNP microarray revealed that physical distance within the colony did not correlate with genetic distance.
Why it matters
The shared power-law mutation distribution between modular corals and human tissues reveals conserved evolutionary features of somatic mosaicism during aging. Establishing somatic mutation rates in long-lived colonial animals also provides a molecular clock to date organisms lacking traditional chronological markers.
Caveats
The investigation examined only eight colonies of a single coral species from one geographic location. Microarray analysis of intra-branch physical distance was limited to 28 samples taken from a single colony.
The paper
Mosaic Accumulation of Somatic Genetic Variation and Estimates of Age in the Long-Lived Reef-Building Coral Acropora palmata
Conn T, Renton J, Chamberland VF et al.
Molecular Ecology · 1 Oct 2026