A breed of super-sniffer mice has been created by researchers at Hunter College (City University) New York. The mice have a heightened ability to recognize a specific odor. They can further be tuned to different sensitivity levels of smell using human or mouse odor receptors. They can be used to detect land mines and also for novel disease sensors.
It is a transgenic approach to modify the mouse genome and would also help researchers study human odor receptors. It is still not clearly understood how the olfactory system wires itself. Our noses are equipped with the combination of sensory neurons each consisting of a chemical sensor known as a receptor that is responsible for detecting odor. A receptor is selected by a neuron which is the case for humans as well as mice.
Lead investigator Paul Feinstein dabbled with mouse genome. He introduced a DNA for odor receptor transgenically by injecting it directly into the nucleus of a fertilized egg cell. He also added a string of DNA to the sequence to see the alteration of probability for the gene to be chosen. After a few attempts, he discovered a string when copied four times, worked.
To everyone’s surprise, a human receptor gene was inserted into mice successfully which helped to understand human odor coding. The team also found that mice had better sense of smell and were able to avoid unpleasant odor. These tests confirmed that the receptors were present in greater numbers in mice.