PICTURE: Fig. 1: Scheme of the study design. We received blood from each donor for the sequencing of the entire genome. In addition, we received skin biopsies from the donors’ hips, from which … view More
Photo credit: Saini N et al., 2021, PLOS Genetics
For the first time, scientists measured the different types of genomic DNA changes in skin cells and found that ultraviolet (UV) light mutations are particularly common, but black people have less UV damage than white people. Dmitry Gordenin and colleagues from the National Institute for Environmental Health Sciences reported these results on January 14 in PLOS Genetics.
The DNA in our skin cells is damaged from sources inside and outside the body, resulting in genomic changes such as mutations that can lead to cancer. UV light is the main source of these mutations, but by-products of cell metabolism such as free radicals and DNA copying errors that occur during cell division also cause genomic changes. These mutation-causing mechanisms are well known, but no one has been able to accurately measure the relative contributions of each source.
In their new paper, Gordenin and his colleagues quantified the amounts of each type of genomic change by sequencing the genomes of skin cells donated by 21 black and white individuals aged 25 to 79 years. The researchers discovered that the total amount of genomic changes caused by metabolic by-products accumulate as a person ages, while the extent of genomic changes caused by UV damage is not related to a person’s age. In addition, they showed that genomic changes from UV light are common, even in skin cells, which are typically protected from the sun, but were less common in black donors than in white donors.
The researchers suspect that black people may be better protected from UV light due to higher levels of skin pigment melanin. This idea is supported by the fact that blacks have much less skin cancer compared to whites. Overall, the new study provides an accurate estimate of the genomic changes that occur in skin cells due to various types of DNA damage and sets the normal range of somatic genomic changes over a wide range of age groups and races and provides a basis for future research.
The authors add, “The new study provides an accurate estimate of the genomic changes that occur in skin cells due to various types of DNA damage, and sets the normal range of somatic genomic changes over a wide range of ages and races to provide a basis for future Research. “
Peer review; Observational study; People
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Quote: Saini N., Giacobone CK, Klimczak LJ, Papas BN, Burkholder AB, Li JL, et al. (2021) UV exposure, endogenous DNA damage and DNA replication errors shape the spectra of genome changes in human skin. PLoS Genet 17 (1): e1009302. https://doi.org/10.1371/journal.pgen.1009302
Funding: This work was supported by the US National Institute of Health’s Intramural Research Program, Project Z1AES103266, to the DAG. Funders had no role in the design of the study, data collection and analysis, the decision to publish, or the preparation of the manuscript.
Competing interests: The authors have stated that there are no competing interests.
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