September 17, 2012
Link Found Between Reversible ‘Epigenetic’ Marks And Behavior Patterns
redOrbit Staff & Wire Reports - Your Universe Online
Genetic analysis of different types of worker bees has for the first time demonstrated a link between reversible chemical tags on an organism's DNA and their behavioral patterns.Andy Feinberg, a professor of molecular medicine and the director of the Center for Epigenetics at Hopkins' Institute for Basic Biomedical Sciences, and colleagues used a method they called CHARM (comprehensive high-throughput arrays for relative methylation) to investigate the location of the DNA methylation biochemical process in the brains of both "nurse" bees and "forager" bees.
They chose 21 of each type of worker bee, all approximately the same age, and discovered 155 regions of DNA that had different tag patterns in each of the two bee types, the researchers explained in a Sunday statement. The bulk of those were genes that have been known to affect the status of other genes, they said, and once the differences were identified, Feinberg and his colleagues set out to discover whether or not they were permanent.
Knowing that nurses can switch jobs, so to speak, if there are a lack of foragers in a five (and vice-versa), they removed all of the nurses and observed for several weeks while the hive restored the balance. Once that was completed, they again studied the DNA methylation patterns to determine whether or not the tags had changed in the foragers that became nurses.
In fact, 107 DNA regions had shown changes in the tags, "suggesting that the epigenetic marks were not permanent but reversible and connected to the bees' behavior and the facts of life in the hive," the researchers said.
Furthermore, "more than half of those regions" -- 57, to be precise -- "had already been identified among the 155 regions that change when nurses mature into foragers," leading Feinberg and his colleagues to determine that those regions "are likely at the heart of the different behaviors exhibited by nurses and foragers."
According to the statement, "The researchers say they hope their results may begin to shed light on complex behavioral issues in humans, such as learning, memory, stress response and mood disorders, which all involve interactions between genetic and epigenetic components similar to those in the study. A person's underlying genetic sequence is acted upon by epigenetic tags, which may be affected by external cues to change in ways that create stable — but reversible — behavioral patterns."
The findings are published in Nature Neuroscience.