Alignment-Free k-mer Analysis Reveals Age-Associated k-mer Signals in Canine Buccal DNA and Cell-Free DNA

Alignment-free k-mer analysis identifies age-associated sequence composition signals in canine buccal DNA (1,187 samples) and cfDNA (100 samples), with stronger patterns in buccal DNA.

• Why it matters: DNA methylation biomarkers can predict age, but alignment-free sequence methods for capturing age-linked signals in canine DNA remain underexplored.
• What they did: Whole-genome sequencing datasets were analyzed with k-mer correlation to find age-associated k-mers, motif and nucleotide composition characterization, and ridge regression to predict age from k-mer frequencies.
• The result: Buccal-derived k-mers showed more pronounced motif patterns and GC/AT enrichment trends and achieved improved age-prediction versus cfDNA; simulations reproduced major enrichment trends and signals were largely preserved after restricting to read-start composition.

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