Genetic Changes in the Brain Over a Lifetime

Researchers from the Roslin Institute in Edinburgh have found that retrotransposons change the genetic structure of brain cells over time, which may be behind some neurological disorders. Retrotransposons are genes that can be multiplied and re-inserted into the genome. They can have effects on the cell if they’re inserted in or near other genes that encode proteins, since they can change how, when or if those proteins are made. Because retrotransposons can be multiplied, they make up a huge proportion of genomes – in our case, around half. 

Brain cells are probably the most interesting type of cells to study in this respect since they can generally survive for your entire lifetime, meaning that individual cells can accumulate quite a bit of genetic changes and become very genetically distinct from their neighbours. If they kept multiplying over our lifetimes like other kinds of cells, those changes would instead be passed on to new cells and the population would not end up being as different. 

From Medical Xpress:

The team, from the Roslin Institute in Edinburgh, studied the DNA structure from brain cells from three deceased people who died from non-brain related incidents and who were otherwise normal and healthy; focusing most specifically on the hippocampus and caudate nucleus. In so doing they were able to identify 25,000 areas where there was evidence that retrotransposons had inserted themselves. In addition, they found evidence of three distinct families of retrotransposons, one of which, the Alu family, had never before been seen in the brain…

They also found that they copied themselves into the genetic material in cells that make up some of the most important parts of the brain, such as chemical transporters. Also notably, some were found in the genes in some cells that are known to fight tumor growth, leading to speculation that they might in fact contribute to certain types of brain cancers. Adding fuel to that fire were retrotransposons found in cells that regulate proteins in the brain which of course have been linked to all manner of psychiatric ailments such as schizophrenia.

They also found a lot more copying went on in the hippocampus then in the caudate nucleus, something that could lead to speculation regarding the nature of memory and learning in general if the cells in that part of the brain have individualized DNA structures.

Genetics and neurobiology are both relatively new fields, so there have been and will be pretty awesome breakthroughs in both, of which this seems to be one. Things always end up being way more complicated than we thought, but these are also great opportunities for breakthroughs in medicine and technology. I look forward to seeing how this changes the field. 

The BBC also has an article on this, out of which I’d like to share just one gem:

They say their discovery completely overturns previous theories about how the brain works.

Wow. I guess we can throw out our biology textbooks then.

One would hope that this huge claim was put into some kind of context, but it wasn’t. This is a really silly statement that I would hope is a misrepresentation of what the authors actually may have said. This is why it’s generally better to read science news websites like PhysOrg or ScienceDaily than to read newspapers’ science sections, if you’re willing to wade deeper into science. 

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