brain plasticity: loaded with new mutations (Introduction)

by David Turell , Saturday, October 03, 2015, 14:43 (3340 days ago) @ David Turell

As neurons are used they mutate. To me this is another form of brain plasticity in somatic cells of the brain, not germ cells. This means each of us has a unique brain based on how we have used it, but those characteristics are not heritable.:-http://www.sciencedaily.com/releases/2015/10/151001153926.htm-"As we grow, our brain cells develop different genomes from one another, according to new research from Harvard Medical School and Boston Children's Hospital.-"The study, published Oct. 2 in Science, shows for the first time that mutations in somatic cells--that is, any cell in the body except sperm and eggs--are present in significant numbers in the brains of healthy people. This finding lays the foundation for exploring the role of these post-conception mutations in human development and disease.-***-"Already, the researchers have discovered that somatic mutations appear to occur more often in the genes a neuron uses most. They have also been able to trace brain cell lineages based on patterns of mutation.-"'These mutations are durable memory for where a cell came from and what it has been up to," said the study's co-senior author, Christopher A. Walsh, the HMS Bullard Professor of Pediatrics and Neurology and chief of the Division of Genetics and Genomics at Boston Children's. "This work is a proof of principle that if we wanted to, and if we had unlimited resources, we could actually decode the whole pattern of development of the human brain."-"'I believe this method will also tell us a lot about healthy and unhealthy aging as well as what makes our brains different from those of other animals," Walsh added.-***-"Walsh, Park and team studied a particular kind of somatic mutation called single nucleotide variants. Each variant may occur in just a few cells, or even just one, so they can be hard to detect with whole-genome sequencing analyses that average hundreds of thousands of cells. Sequencing individual cells brings the rare mutations to light.-***-"Many phenomena can create somatic mutations. Ultraviolet light causes them in skin cells. Errors in DNA replication cause them in rapidly dividing cancer cells.-"'What we found in the brain was neither of those things," said Walsh. "We thought the dominant source of mutation would be faulty DNA replication and were surprised to find that instead, it's faulty DNA expression."-"Park's data analysis revealed that the genes with the most mutations tended to be the ones that were used most in the brain.-"'People like to say about your brain, 'use it or lose it.' Unfortunately, we found there's a certain element of 'use it and lose it,'" said Walsh. "Every time you turn on a gene, there is at least some level of risk."-***-"'I'm full of mutations but I'm walking around, pretty healthy," said Park. "It just goes to show that there are a lot of things we don't understand.'"-Comment: He doesn't understand it because he doesn't look for purpose like I do. Romansh?