Featured Research

from universities, journals, and other organizations

Cat and mouse: One gene is necessary for mice to avoid predators

Date:
April 29, 2013
Source:
Northwestern University
Summary:
A new study involving olfactory receptors provides evidence that a single gene is necessary for a mouse to avoid a cat. A research team has shown that removing one olfactory receptor from mice can have a profound effect on their behavior. The gene, called TAAR4, encodes a receptor that responds to a chemical that is enriched in the urine of carnivores. While normal mice innately avoid the scent marks of predators, mice lacking the TAAR4 receptor do not.

Cat with a mouse in her paws.
Credit: cynoclub / Fotolia

When a mouse smells a cat, it instinctively avoids the feline or risks becoming dinner. How? A Northwestern University study involving olfactory receptors, which underlie the sense of smell, provides evidence that a single gene is necessary for the behavior.

A research team led by neurobiologist Thomas Bozza has shown that removing one olfactory receptor from mice can have a profound effect on their behavior. The gene, called TAAR4, encodes a receptor that responds to a chemical that is enriched in the urine of carnivores. While normal mice innately avoid the scent marks of predators, mice lacking the TAAR4 receptor do not.

The study, published April 28 in the journal Nature, reveals something new about our sense of smell: individual genes matter.

Unlike our sense of vision, much less is known about how sensory receptors contribute to the perception of smells. Color vision is generated by the cooperative action of three light-sensitive receptors found in sensory neurons in the eye. People with mutations in even one of these receptors experience color blindness.

"It is easy to understand how each of the three color receptors is important and maintained during evolution," said Bozza, an author of the paper, "but the olfactory system is much more complex."

In contrast to the three color receptors, humans have 380 olfactory receptor genes, while mice have more than 1,000. Common smells like the fragrance of coffee and perfumes typically activate many receptors.

"The general consensus in the field is that removing a single olfactory receptor gene would not have a significant effect on odor perception," said Bozza, an assistant professor of neurobiology in the Weinberg College of Arts and Sciences.

Bozza and his colleagues tested this assumption by genetically removing a specific subset of olfactory receptors called trace amine-associated receptors, or TAARs, in mice. Mice have 15 TAARs. One is expressed in the brain and responds to amine neurotransmitters and common drugs of abuse such as amphetamine. The other 14 are found in the nose and have been coopted to detect odors.

Bozza's group has shown that the TAARs are extremely sensitive to amines -- a class of chemicals that is ubiquitous in biological systems and is enriched in decaying materials and rotting flesh. Mice and humans typically avoid amines since they have a strongly unpleasant, fishy quality.

Bozza's team, including the paper's lead authors, postdoctoral fellow Adam Dewan and graduate student Rodrigo Pacifico, generated mice that lack all 14 olfactory TAAR genes. These mice showed no aversion to amines. In a second experiment, the researchers removed only the TAAR4 gene. TAAR4 responds selectively to phenylethylamine (PEA), an amine that is concentrated in carnivore urine. They found that mice lacking TAAR4 fail to avoid PEA, or the smell of predator cat urine, but still avoid other amines.

"It is amazing to see such a selective effect," Dewan said. "If you remove just one olfactory receptor in mice, you can affect behavior."

The TAAR genes are found in all mammals studied so far, including humans. "The fact that TAARs are highly conserved means they are likely important for survival," Bozza said.

One idea is that the TAARs may make animals very sensitive to the smell of amines. Humans may have TAAR genes to avoid rotting foods, which become enriched in amines during the decomposition process. In fact, the TAARs may relay information to a specific part of the brain that elicits innately aversive behavior in animals.

Bozza's lab has recently shown that neurons in the nose that express the TAARs connect to with a specific region of the olfactory bulb -- the part of the brain that first receives olfactory information. This suggests that the TAARs may elicit hardwired responses to amines in mice, and perhaps humans.

"We hope this work will reveal specific brain circuits that underlie instinctive behaviors in mammals," Bozza said. "Doing so will help us understand how neural circuits contribute to behavior."


Story Source:

The above story is based on materials provided by Northwestern University. The original article was written by Megan Fellman. Note: Materials may be edited for content and length.


Journal Reference:

  1. Adam Dewan, Rodrigo Pacifico, Ross Zhan, Dmitry Rinberg, Thomas Bozza. Non-redundant coding of aversive odours in the main olfactory pathway. Nature, 2013; DOI: 10.1038/nature12114

Cite This Page:

Northwestern University. "Cat and mouse: One gene is necessary for mice to avoid predators." ScienceDaily. ScienceDaily, 29 April 2013. <www.sciencedaily.com/releases/2013/04/130429154115.htm>.
Northwestern University. (2013, April 29). Cat and mouse: One gene is necessary for mice to avoid predators. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2013/04/130429154115.htm
Northwestern University. "Cat and mouse: One gene is necessary for mice to avoid predators." ScienceDaily. www.sciencedaily.com/releases/2013/04/130429154115.htm (accessed August 22, 2014).

Share This




More Plants & Animals News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Endangered Red Wolves Face Uncertain Future

Endangered Red Wolves Face Uncertain Future

AP (Aug. 22, 2014) A federal judge temporarily banned coyote hunting to save endangered red wolves, but local hunters say that the wolf preservation program does more harm than good. Meanwhile federal officials are reviewing its wolf program in North Carolina. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Farm Resurgence Grows With Younger Crowd

Farm Resurgence Grows With Younger Crowd

AP (Aug. 22, 2014) New England farms are seeing a surge in younger farm hands as the 'buy local' food movement grows across the country. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) According to a new study, spiders that live in cities are bigger, fatter and multiply faster. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins