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Published online: 13 August 2008 | doi:10.1038/nchina.2008.186
Eukaryotes: Changes enclosed
Jasmine Farsarakis
Abstract
Genome comparisons of eukaryotes, including primates, rodents, fruit flies, rice and yeast, show that single-nucleotide mutations occur most frequently around sequence insertions and deletions
Original article citation
et al. Single-nucleotide mutation rate increases close to insertions/deletions in eukaryotes. Nature doi: 10.1038/nature07175 (2008).Introduction
© (2008) istockphoto.com/Christian Anthony
Regions of frequent mutations in the genome, or 'mutation hotspots', drive the rapid evolution of living organisms. Little is known, however, regarding the general mechanisms for their formation. Dacheng Tian and Jianqun Chen at Nanjing University and co-workers1 have provided evidence that regions surrounding sequence insertions or deletions (indels) of the genome have increased rates of single-nucleotide mutations.
Mutations are thought to be the result of the compositional or structural properties of certain sequences, combined with, or solely attributed to, the intensity of natural selection. The researchers tested their own hypothesis regarding genetic mutations, that indels have a causative role in single-nucleotide mutations. By performing genomic comparisons in six different species, including humans, chimpanzees, rhesus macaques, mice and rats, they found that nucleotide diversity was substantially increased in the genomic regions surrounding indels. Further analyses showed a significant correlation between size and abundance of indels in the genome and nucleotide diversity.
Comparison studies of closely related species also determined that heterozygocity for an indel can increase the risk of mutations in the surrounding sequences. As these results were consistent between and within species, the researchers concluded that the indel-associated substitution mechanism is valid in all eukaryotes.
The authors of this work are from:
State Key Laboratory of Pharmaceutical Biotechnology, Department of Biology, Nanjing University, Nanjing, China; Department of Fish Ecology and Evolution, EAWAG Center of Ecology, Evolution and Biogeochemistry, Kastanienbaum, Switzerland; Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA.
Reference
- Tian, D. et al. Single-nucleotide mutation rate increases close to insertions/deletions in eukaryotes. Nature doi: 10.1038/nature07175 (2008). | Article |
