Whole-genome comparison reveals distinct somatic mutation landscapes in cartilage and skin cells

Researchers including Safia Mahabub Sauty, Dmitry A. Gordenin, and colleagues at institutions including the University of North Carolina have published comparative whole-genome analyses of articular chondrocytes (the cells lining joint cartilage) and skin fibroblasts in PLOS Genetics. Both cell types derive from the mesoderm during embryonic development, yet the study demonstrates that their somatic mutation landscapes — the patterns of DNA changes that accumulate in cells over time — are substantially different.

The team characterised mutational signatures, structural variants, and copy-number alterations across the two cell types, finding that differences in physiological environment, metabolic activity, mutagenic exposure, and DNA repair efficiency each contribute to the distinct genomic profiles observed. Articular chondrocytes, which exist in a low-oxygen, mechanically loaded environment, displayed a different spectrum of lesions from the UV-exposed, proliferating fibroblasts of the skin.

The findings are relevant to understanding how somatic genome instability contributes to conditions such as osteoarthritis and to age-related changes more broadly. The study also illustrates how tissue-specific mutational processes need to be accounted for in somatic genomics research, where reference datasets often conflate cell types of shared developmental lineage.