Featured Research

from universities, journals, and other organizations

Extensive taste loss found in mammals: Feeding preferences shaped by taste receptors

Date:
March 12, 2012
Source:
Monell Chemical Senses Center
Summary:
Scientists report frequent loss of sweet taste in mammalian species that are exclusive meat eaters. Further, two sea-dwelling mammals that swallow their food whole have extensive taste loss. Many sweet-blind species eat only meat, demonstrating that a liking for sweets is frequently lost during the evolution of diet specialization.

A cat investigates a candy. It may look interesting, but cats are unable to taste sweet. Cats are obligate carnivores, meaning that they subsist only on meat.
Credit: © Paty Wingrove / Fotolia

Scientists from the Monell Center report that seven of 12 related mammalian species have lost the sense of sweet taste. As each of the sweet-blind species eats only meat, the findings demonstrate that a liking for sweets is frequently lost during the evolution of diet specialization.

Previous research from the Monell team had revealed the remarkable finding that both domestic and wild cats are unable to taste sweet compounds due to defects in a gene that controls structure of the sweet taste receptor.

Cats are obligate carnivores, meaning that they subsist only on meat. In the current study, published online in Proceedings of the National Academy of Sciences, the Monell scientists next asked whether other strict carnivores have also lost the sweet taste receptor.

To do this, they examined sweet taste receptor genes from 12 related mammalian species with varying dietary habits. They once again found taste loss and to their surprise, it was widespread in the meat-eating species.

Senior author Gary Beauchamp, Ph.D., a behavioral biologist at Monell, comments, “Sweet taste was thought to be nearly a universal trait in animals. That evolution has independently led to its loss in so many different species was quite unexpected.”

The integrity of the sweet taste receptor gene was closely related to the animals’ diets. Sea lion, fur seal, Pacific harbor seal, Asian otter, spotted hyena, fossa, and banded lingsang, species that are exclusive meat eaters, all had defective sweet receptor genes.

In contrast, intact sweet receptor genes were found in aardwolf, Canadian otter, spectacled bear, raccoon, and red wolf. These species include both exclusive meat-eaters and those that also eat other foods in addition to meat.

Further examination revealed that the defective portion of the sweet receptor gene varies among the seven species with non-intact receptors. Together, the findings suggest that diet-related taste loss has happened repeatedly and independently throughout evolution, demonstrating the importance of dietary niche in the structure and function of an animal’s sensory system.

To further explore the relationship between feeding behavior and taste function, the researchers next examined sweet and umami (savory) taste receptor genes in two mammals that have “returned” to the sea, the sea lion and bottlenose dolphin. These animals were selected because they swallow their food whole, suggesting that taste may not play an important role in their dietary selection.

As predicted, taste loss was extensive in these animals. Sweet and umami receptor genes were nonfunctional in both, and the dolphin also had nonfunctional bitter taste receptor genes.

“Different animals live in different sensory worlds and this particularly applies to their worlds of food. Our findings provide further evidence that what animals like to eat - and this includes humans - is dependent to a significant degree on their basic taste receptor biology,” said Beauchamp.

The current research raises questions beyond diet choice, as taste receptors have recently been identified in many organs throughout the body, including intestine, pancreas, nose, and lungs. These extra-oral taste receptors are believed to serve many different functions.

“Our findings clearly show that the extra-oral taste receptors are not needed for survival in certain species,” notes lead author Peihua Jiang, Ph.D., a molecular biologist at Monell. “The animals we examined did not have functional sweet, umami, or bitter taste receptors, so it will be important to identify how their functions were replaced throughout the body.”

Also contributing to the research were Monell scientists Jesusa Josue, Xia Li, Weihua Li, Joseph G. Brand, Robert F. Margolskee, and Danielle R. Reed, and Dieter Glaser of the University of Zurich. Funding was provided by National Institute on Deafness and Other Communication Disorders and institutional funds from the Monell Chemical Senses Center.


Story Source:

The above story is based on materials provided by Monell Chemical Senses Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Peihua Jiang, Jesusa Josue, Xia Li, Dieter Glaser, Weihua Li, Joseph G. Brand, Robert F. Margolskee, Danielle R. Reed, and Gary K. Beauchamp. Major taste loss in carnivorous mammals. Proceedings of the National Academy of Sciences, March 12, 2012 DOI: 10.1073/pnas.1118360109

Cite This Page:

Monell Chemical Senses Center. "Extensive taste loss found in mammals: Feeding preferences shaped by taste receptors." ScienceDaily. ScienceDaily, 12 March 2012. <www.sciencedaily.com/releases/2012/03/120312152639.htm>.
Monell Chemical Senses Center. (2012, March 12). Extensive taste loss found in mammals: Feeding preferences shaped by taste receptors. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/03/120312152639.htm
Monell Chemical Senses Center. "Extensive taste loss found in mammals: Feeding preferences shaped by taste receptors." ScienceDaily. www.sciencedaily.com/releases/2012/03/120312152639.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
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