Structural variation in repeat elements is widespread in normal human tissues and in tumorigenesis
Somatic mosaicism contributes to genomic variation, yet postzygotic structural variants remain under-characterized. We performed long- and short-read WGS from multiple individuals (n=47 normal tissues; n=168 samples) and identified mosaic structural variants in all individuals and germ layers, impacting a median 285.2 kb/genome. Nearly half of breakpoints were independently validated, with tissue…
A study published in <source 56b64488-a78> has revealed that repeat element variations are common in both normal human tissues and cancer. The research, which analyzed 47 normal tissues and 168 samples across multiple individuals, identified structural variants in each of the germ layers. These variants, which can impact up to 285.2 kb of the genome, were found to be widespread across all examined tissues, with their distribution hinting at origins from both early and later stages of development.
Most of these variants were found to be repeat-mediated, with 8.3% of them overlapping functional elements, a higher percentage than seen in germline variants. To further explore these variants in samples where long-read sequencing might not be possible, the researchers turned to short-read sequencing to detect repeat alterations, successfully reproducing the tissue-specific differences observed in longer reads.
The study extended its scope to 15 types of cancer, discovering that tumor-specific variations in repeats were on par with those found in normal tissues. Additionally, tracking repeat changes in cell-free DNA has been identified as a noninvasive method for monitoring tumors. Overall, the findings underline the widespread occurrence of repeat-driven structural variation in both healthy and diseased states.
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