Word: gene
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
Maze's research focused on a particular protein called G9a that is associated with cocaine-related changes in the nucleus accumbens, a brain region essential for the experience of desire, pleasure and drive. The role of the protein appears to be to shut down genes that shouldn't be on. One-time use of cocaine increases levels of G9a. But repeated use works the other way, suppressing the protein and reducing its overall control of gene activation. Without enough G9a, those overactive genes cause brain cells to generate more dendritic spines, which are the parts of cells that make connections...
...these spines can reflect learning. But in the case of addiction, that may involve learning to connect a place or a person with the desire for more drugs. Maze showed that even after a week of abstinence, mice given a new dose of cocaine still had elevated levels of gene activation in the nucleus accumbens, meaning G9a levels were still low. It is not known how long these changes can last. Maze also showed that when he intervened and raised G9a levels, the mice were less attracted to cocaine...
Other recent studies have also shown the power of environment over gene expression. For instance, fruit flies exposed to a drug called geldanamycin show unusual outgrowths on their eyes that can last through at least 13 generations of offspring even though no change in DNA has occurred (and generations 2 through 13 were not directly exposed to the drug). Similarly, according to a paper published last year in the Quarterly Review of Biology by Eva Jablonka (an epigenetic pioneer) and Gal Raz of Tel Aviv University, roundworms fed with a kind of bacteria can feature a small, dumpy appearance...
...vitamins acted as methyl donors: they caused methyl groups to attach more frequently to the agouti gene in utero, thereby altering its expression. And so without altering the genomic structure of mouse DNA - simply by furnishing B vitamins - Jirtle and Waterland got agouti mothers to produce healthy brown pups that were of normal weight and not prone to diabetes...
...Been Told About Genetics, Talent and IQ Is Wrong, science writer David Shenk says epigenetics is helping usher in a "new paradigm" that "reveals how bankrupt the phrase 'nature versus nurture' really is." He calls epigenetics "perhaps the most important discovery in the science of heredity since the gene." (See the top 10 nonfiction books...