Cortical convolutions controlled in sections: Non-coding DNA sequence affects brain"s characteristic folding, study shows

http://feeds.feedburner.com/~r/sciencedaily/top_news/top_health/~4/99A6gIDiJgM

Researchers have tied a particular gene to the development of cortical convolutions — the prominent but enigmatic folds covering the surface of the human brain. Their discovery should shed some light on these characteristic contours, which have been the subject of wild speculation for ages, and perhaps also provide a better understanding of how such brain ridges form, how they evolved from our pre-human ancestors and, ultimately, how they influence brain function.The exact role of cortical convolutions remains unknown, but theories have abounded. (Some, for example, have suggested that the folds act as the body’s cooling system and others have even proposed that Albert Einstein’s genius could have been traced to a single cortical fold on his brain.)Now, leveraging advances that permit a closer look at how these folds develop, research published in the 14 February issue of Science shows that a mutation affecting GPR56 causes cortical convolutions around the brain’s Sylvian fissure — a particularly deep indentation — to develop thinner and more convoluted than usual. The finding, which suggests that genes may assert control over the brain’s physical folding on a section-by-section basis, provides insight into the mysterious cortical development process.”There is already a list of genetic mutations that cause abnormal neocortical folding, which can be used for prenatal testing,” explained Byoung-il Bae from the Division of Genetics and Genomics at Boston Children’s Hospital and Harvard Medical School in Boston, Massachusetts, one of the lead authors of the Science report. “We intend to add this mutation to some of the panels.”Bae and colleagues from around the world investigated the genomes of five individuals with abnormalities on Broca’s area, or the language center of the brain. These study participants were from three different families — one Turkish and two Irish-American — and they suffered from refractory seizures as well as intellectual and language difficulties.The researchers found that all five patients harbored a mutation on a particular regulatory element that influences the GPR56 gene. Such regulatory DNA doesn’t code for any proteins itself but promotes the expression of genes elsewhere on the genome. Geneticists have long-suspected that such non-coding regions of the genome could play important roles in evolution. To observe the specific effects of the GPR56 “promoter” DNA sequence, Bae and his team used genetically modified mice.They discovered that low expression of GPR56 (gauged by low levels of mRNA) decreases the production of neuroprogenitor cells — those that will eventually give rise to neurons — around Broca’s area and the Sylvian fissure. By contrast, overexpression of the gene boosts the production of such progenitor cells in that region. …


Read More: Cortical convolutions controlled in sections: Non-coding DNA sequence affects brain"s characteristic folding, study shows

#Alternative-Medicine, #Discovery, #Education, #Health, #Medical, #Pregnancy, #Rna, #School, #Speculation, #Technology, #Wild, #World