Biologists at Harvard University and the University of California, San Diego, have found that a simple interaction between just two genes determines the patterns of fur coloration that camouflage mice against their background, protecting them from many predators. The work, published this week in the journal PLoS Biology, marks one of the few instances in which specific genetic changes have been linked to an organism's ability to survive in the wild.
"Our work shows how changes in just a few genes can greatly alter an organism's appearance," says Hopi E. Hoekstra, John L. Loeb Associate Professor of the Natural Sciences in Harvard's Faculty of Arts and Sciences. "It also illuminates the pathway by which these two genes interact to produce distinctive coloration. There's reason to believe this simple pathway may be evolutionarily conserved across mammals that display lighter bellies and darker backs, from mice to tuxedo cats to German Shepherds."
Hoekstra and co-authors Cynthia C. Steiner at UCSD and Jesse Weber at Harvard studied Peromyscus, a mouse that is the most widespread mammal in North America. Within the last several thousand years, these mice have migrated from mainland Florida to barrier islands and dunes along the Atlantic and Gulf coasts, where they now live on white sand beaches. In the process, the beach mice's coats have become markedly lighter than that of their mainland brethren.
"In nature there is a tremendous amount of variation in color patterns among organisms, ranging from leopard spots to zebra stripes, that help individuals survive," says Steiner, a postdoctoral researcher in UCSD's Division of Biological Sciences. "However, we know surprisingly little about how these adaptive color patterns are generated. In this paper, we identify the genetic changes producing a simple color pattern that helps camouflage mice inhabiting the sandy dunes of Florida's Gulf and Atlantic coasts. These 'beach mice' have evolved a lighter pigmentation than their mainland relatives, a coloration that helps camouflage them from predators that include owls, herons, and hawks."
Previous research has shown that such predators, all of which hunt by sight, will preferentially catch darker mice on the white sand beaches, providing a powerful opportunity for natural selection to evolve increased camouflage.
Through a detailed genomic analysis, Hoekstra, Steiner, and Weber identified two pigmentation genes, for the melanocortin-1 receptor (Mc1r) and an agouti signaling protein (Agouti) that binds to this receptor and turns it off. A single amino-acid mutation in Mc1r gene can weaken the receptor's activity, or a mutation in the Agouti gene can increase the amount of protein present without changing the protein's sequence, also reducing Mc1r activity and yielding lighter pigmentation.
Both genes affect the type and amount of melanin in individual hairs. When both genes are turned on, the mouse is dark in color. A mutation that changes either gene leads to a somewhat blonder mouse, but it is the combination of mutations in both genes that produces a mouse very light in color.
"Thus, two different types of mutations in two different genes each contribute to the light coloration of beach mice," Hoekstra says. "This work represents a first step into understanding how unique patterns of fur color are produced via a simple interaction between genes."
Steve Bradt | EurekAlert!
What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society
Treating arthritis with algae
23.08.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
23.08.2017 | Life Sciences
23.08.2017 | Life Sciences
23.08.2017 | Physics and Astronomy