In 1954, America first saw color television.
In 2006, mice at Johns Hopkins University finally figured out what all the fuss was about.
Mouse embryos injected with stem cells containing color vision genes grew into adult animals that could distinguish between their parent?s blue and green hues, and the reds that humans and other primates can see, according to research from Johns Hopkins School of Medicine in Baltimore City and University of California, Santa Barbara.
“The main interest is in sort of reconstructing the evolutionary history of our own color vision,” said lead researcher Dr. Jeremy Nathans, professor of molecular biology and genetics, neuroscience and ophthalmology at Hopkins.
Their research countered one theory of evolution that the brain would have to evolve some receptor capacity before it could interpret the new signals from the eye, Nathans said.
“The brain has an inherent flexibility and a plasticity,” he said.
This work, appearing today in Science, also suggests that when early primates inherited a new type of photoreceptor ? more than 40 million years ago according to evolutionary theory ? they probably experienced immediate color enhancement, allowing the trait to spread quickly.
Nathans and his team set mice before three light panels and trained them to touch the panel that appeared different. A correct answer earned a drop of soy milk.
Normal mice can?t distinguish yellow from red lights, according to the article.
But mice with both the human long wavelength ? red ? and the mouse middle wavelength ? green ? receptors learned to tell the difference, after about 10,000 trials.
The National Eye Institute and Howard Hughes Medical Institute funded the research, and authors included Hugh Cahill of Johns Hopkins and colleagues from California.
Next, Nathans said he hopes to learn how the brain adapted so quickly.
“Were curious about what the calculation is that?s going on in the brain of the mouse,” he said.
For details, visit neuroscience.jhu.edu/index.php or www.sciencemag.org.
