Widespread RNA/DNA Mismatch
Vivian G. Cheung, MD
University of Pennsylvania
NIEHS Grant R01ES015733
A University of Pennsylvania grantee reports that when DNA is transcribed into RNA, the RNA copy is a lot less exact than previously thought. The findings, published in Science, report these mistakes or differences result in proteins that do not exactly match the genes that encode them suggesting a new unexplored area of variation in the human genome.
The researchers sequenced the genomes of 27 individuals. They found more than ten thousand places where the RNA did not match the DNA. At first they thought the differences might be attributable to technical problems, but numerous experiments confirmed the results. While performing these extra experiments, they noticed that many times, a single RNA base was always changed in exactly the same manner. For example, a site that should be AA was always AC. Every individual would either have the original AA or the edited AC but no other possible changes.
These changes resulted in protein differences that ranged from minor single amino acid substitutions to a protein that was 55 amino acids longer than it should have been. At this point, the researchers do not know how these changes occur or the implications of the resulting differences in protein structure and function. Further research is necessary to understand any effects resulting from these changes such as differences in susceptibility to certain diseases.
Citation: Citation: Li M, Wang IX, Li Y, Bruzel A, Richards AL, Toung JM, Cheung VG. Widespread RNA and DNA sequence differences in the human transcriptome. Science. 2011 Jul 1;333(6038):53-58.
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