Copy number variations (CNVs) capture 17.7% of the total detected genetic variation in gene expression levels across the analyzed transcripts. While CNVs represent a measurable source of heritable variation affecting gene expression, their contribution is substantially lower than that of SNPs. [@stranger_relative_2007]
Definitions
Synthesis
Multiple sources establish that copy number variations contribute meaningfully to gene expression variation but play a distinctly secondary role compared to single nucleotide polymorphisms, with CNVs accounting for approximately 18% of detectable genetic variation in transcript abundance while SNPs capture the dominant 84% share across thousands of transcripts in the HapMap population. The mechanistic basis for this asymmetry appears to involve fundamentally different pathways, as SNP and CNV signals show minimal overlap in their associations with gene expression, suggesting these variant types operate through independent or non-overlapping regulatory mechanisms. While the relative contributions are quantified, what remains less clear is why CNVs—despite their potential for larger-scale genomic changes—exert comparatively modest effects on expression architecture, and whether the non-overlapping nature of SNP and CNV signals reflects truly distinct molecular mechanisms or differences in detection sensitivity and study design.
Related
- Interrogating both SNPs and CNVs is necessary for understanding complex phenotypes
- SNP and CNV signals show minimal overlap in gene expression associations
- SNPs capture majority of genetic variation affecting gene expression