Shrews preparing for winter (Solex Araneus) shrink the brain Reduce by 30% to save precious energy. Then, in the spring, the shrew miraculously “regenerates” its shriveled brain, with its neurons completely intact.
Scientists are now tracing the evolutionary origins of this rare adaptation and the genes that may make it possible. While this information is fascinating in itself, it also has the potential to spark new approaches to understanding and treatment. degeneration of the human brain.
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This unusual adaptation is known as Denel phenomenonnamed after a Polish zoologist august dehnelHe was the first to describe the shrew’s remarkable ability to shrink its brain, a way to cope with seasonal energy shortages.
Denel phenomenon is rare, but shrews are not the only species that suffers from it. European mole (Talpa Europe), Itachi (Itachi), stoat (Itachi Herminea) Brain size also decreases with the seasons. Both of these mammals have fast metabolisms and do not hibernate, which may explain why they take such drastic steps to reduce their energy needs when food is scarce.
Ecologist William Thomas of Stony Brook University led a study to map the shrew’s entire genome and compare it to the genomes of other mammals that also exhibit the Denel phenomenon to see what genetic tricks it has evolved.
This study is based on input from the team previous workIn this study, we looked at seasonal changes in gene expression in two parts of the shrew’s brain and determined which parts of the DNA are more active and therefore potentially involved during these large-scale body changes.
Taking their data together, the researchers found that genes related to brain cell production are upregulated across multiple species that exhibit the Daner phenomenon.
The shrew in particular had the following expressions on its face: Begufaa gene associated with blood-brain barrier permeability (which may improve the sensing of nutrients in the brain). Its genome was also rich in genes related to DNA repair and lifespan.
Moisture regulating genes are also activated, supporting theory Shrews reversibly reduce brain volume by losing waternot a net brain cell.
The findings demonstrate “a finely tuned system that allows shrews to reversibly regulate brain shrinkage while avoiding the deleterious effects typically associated with neurodegeneration,” the researchers said. write In their published papers.
Aurora Luis Herrera, a cell biologist at the Autonomous University of Barcelona add: “The role of genes related to energy homeostasis and the blood-brain barrier presents potential biomarkers and therapeutic targets. neurodegenerative diseasesAlways use the necessary caution when extrapolating to humans. ”
This study molecular biology and evolution.