Are mutations truly random?

Do genetic mutations really occur at random spots along the genome, as researchers have long supposed? Maybe not, according to a study published online today (January 13) in Proceedings of the Royal Society B, which proposes a mechanism for how new mutations might preferentially form around existing ones. Image: Wikimedia commons, Jerome Walker, Dennis Myts"The idea is quite interesting," said evolutionary geneticist linkurl:Maud Tenaillon;http://moulon.inra.fr/pages_pers/tenaillon/ of the Un

Jef Akst
Jan 12, 2010
Do genetic mutations really occur at random spots along the genome, as researchers have long supposed? Maybe not, according to a study published online today (January 13) in Proceedings of the Royal Society B, which proposes a mechanism for how new mutations might preferentially form around existing ones.
Image: Wikimedia commons,
Jerome Walker, Dennis Myts
"The idea is quite interesting," said evolutionary geneticist linkurl:Maud Tenaillon;http://moulon.inra.fr/pages_pers/tenaillon/ of the University of California, Irvine, who was not involved in the research. "I think it could be a good explanation for [mutational] hotspots." But, she cautioned, the support for this hypothesis so far falls solely on a somewhat incomplete theoretical model. Single nucleotide polymorphisms (SNPs) exist in clusters of varying size and density across the genome. Despite this non-random distribution, scientists believed for many years that these so-called mutational hotspots were the product of natural selection and other post-mutational processes, and that the...
The ScientistRoyal SocietyClarification: In the original version of this story, a quote from Amos could have been misinterpreted to mean that mutations occurring under the proposed nonrandom mechanism were more likely to be beneficial than deleterious. Rather, the chance of being beneficial will be higher under this mechanism than if mutations occurred randomly.