Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Making mice with enhanced color vision

Researchers at the Johns Hopkins School of Medicine and their colleagues have found that mice simply expressing a human light receptor in addition to their own can acquire new color vision, a sign that the brain can adapt far more rapidly to new sensory information than anticipated.

This work, appearing March 23 in Science, also suggests that when the first ancestral primate inherited a new type of photoreceptor more than 40 million years ago, it probably experienced immediate color enhancement, which may have allowed this trait to spread quickly.

"If you gave mice a new sensory input at the front end, could their brains learn to make use of the extra data at the back end?" asks Jeremy Nathans M.D., Ph.D., professor of molecular biology and genetics, neuroscience, and ophthalmology at Hopkins. "The answer is, remarkably, yes. They did not require additional generations to evolve new sight."

Retinas of primates such as humans and monkeys are unique among mammals in that they have three visual receptors that absorb short (blue), medium (green) and long (red) wavelengths of light. Mice, like other mammals, only have two; one for short and one for medium wavelengths.

... more about:
»monkeys »photoreceptor »primate »wavelength

In the study, the researchers designed a "knock-in" mouse that has one copy of its medium wavelength receptor replaced with the human long wavelength receptor, so both were expressed in the retina. The human receptors were biologically functional in the mice, but the real question was whether the mice could use the new visual information.

To address this question, the researchers used a classic preference test; mice set before three light panels were trained to touch the one panel that appeared to differ from the other two. A correct answer was rewarded with a drop of soy milk.

To circumvent thorny issues related to the subjective nature of color perception -- everyone who has had a discussion as to whether the "green" they see is the same as the "green" their friend sees can attest to this -- the researchers only tested whether the mice could discriminate among the lights.

"Each photoreceptor absorbs a range of wavelengths, but the efficiency changes with wavelength," Nathans explains. "For example, one photoreceptor might absorb green light only half as efficiently as red light. If an animal had only this type of photoreceptor, then a green light that was twice as bright as a red light would look identical to the red one. But if the animal adds a second photoreceptor with different absorption properties, then by comparing both receptors, the red and green lights could always be distinguished."

Normal mice failed to discriminate yellow versus red lights when the light intensities were set to give equal activation of their middle wavelength receptor. However, mice with both the human long wavelength and the mouse middle wavelength receptors learned to tell the difference, although it took over 10,000 trials to learn to make the distinction.

Nathans suggests that these knock-in mice mimic how our earliest primate ancestors acquired trichromatic vision, color vision based on three receptors. At some point in the past, random mutations created a variant of one receptor gene, located on the X chromosome, producing two different receptor types. Present-day New World (South American) monkeys still use this system, which means that in these monkeys only certain females can acquire trichromatic color vision.

In contrast, among Old World (African) primates such as humans, the two different X chromosome genes duplicated so that each X chromosome now carries the genes for both receptor types, giving both males and females trichromatic color vision.

"You could say that the original primate color vision system, and the one that New World monkeys still use today, is the poor man's -- or to be accurate, poor woman's -- version of color vision," Nathans says.

Nick Zagorski | EurekAlert!
Further information:

Further reports about: monkeys photoreceptor primate wavelength

More articles from Life Sciences:

nachricht When fat cells change their colour
28.10.2016 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Aquaculture: Clear Water Thanks to Cork
28.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>