A gene for stupidity has he been identified?

Smarter mice could be genetically created at Emory University School of Medicine in eliminating its genome a gene restricting learning. Scientists have dubbed the gene Homer Simpson ...

Besides being a pretty little fish, the hippocampus is a structure contained in the brain that takes its name from the fact coiled shape of the animal. Like many brain regions, this structure is associated with a particular role. Thus, the hippocampus is clearly the place of manufacture of souvenirs and probably also involved in the recall of these memories after stimulation (smell, music, voice ...), even if uncertainty remains about its mechanism.

In particular, a region within the hippocampus, whose role remains mysterious. Named CA2 (Ammon's Horn for 2), it is the neighboring regions CA1 and CA3. The role of these two regions is clearly identified yet: they form a neural circuit with another region of the hippocampus (dentate gyrus) through which information travels from neuron to neuron actively and participate in memory processes.

In addition to being functionally independent, CA2 structure seems less active than its neighbors. For example, the synapses of neurons in this region use a simple mechanism for information transmission, while the neighboring regions using the mechanism called long-term potentiation, which allows transmission of information more intense.

In the journal Proceedings of the National Academy of Sciences, the scientists showed another peculiarity of the CA2 region: a signaling protein known as RGS14 "accumulates in large quantities in these neurons. Designed for a decade, this protein is involved in the regulation of cell signaling pathway required for brain processes memory or learning.

Mice that express the protein RGS14 more closely resemble mice but have normal learning abilities superior. © Rama / Creative Commons License

GM smarter ...

To better characterize the role of a protein, one strategy is to eliminate it and observe the consequences. This has been done for the RGS14 protein. Mice have been genetically modified, that is to say that the gene was cut so that the RGS14 protein is no longer expressed. The mice were then analyzed from different angles to highlight differences from normal mice.

The neurons of the CA2 region were first tested. The analysis of the response of these neurons to electrical stimulation showed that the mutation makes now able to provide the complex mechanism of long-term potentiation. Neurons have mutated a stronger response to stimulation than neurons in normal mice.

Then, mice were subjected to behavioral tests. From the perspective of learning, these transgenic mice show enhanced capabilities. They more easily recognize the objects that had already been presented. Furthermore, when placed in a flooded maze, the mutant mice more easily find the platform on which to rest, thanks to the recognition of visual cues.

Since it seems logical that greater learning skills promote survival, why the mouse (or the man who has a homologue protein) has genes that would limit this potential? Especially a priori, these mice do not seem affected by the loss of RGS14 protein. It is possible that RGS14 has been an important but it could not be detected during the experiments. Homer Simpson gene may have less pejorative nickname soon ...