Unlike most mammals, cats--both domestic and wild--are indifferent to sweets. A new study in PLoS Genetics explains the molecular mechanism behind their strictly carnivorous behavior. "We took a behavioral question and answered it molecularly," says Joseph Brand, senior author of the study and Associate Director of the Monell Chemical Senses Center.
Scattered on mammalian tongues are specialized taste bud receptors that recognize specific tastes, including, of course, sweet. Two different proteins hook together to make each sweet receptor. According to Brand, Xia Li (lead author of the study), and their coauthors, cats do not produce one of the proteins, because the gene that codes for it is a pseudogene and is not functional. It is this lack of a functional sweet receptor that explains cats' indifference to sweet stimuli.
Cats have no way to recognize carbohydrates, and therefore eat an "Atkins-like" diet of meat and fat. These findings lead to more questions, Brand says. "The overarching evolutionary questions are: when and why did cats lose the ability to taste sweet things? Which came first, the carnivorous behavior or the inability to taste sweets?"
Brand adds, "I say jokingly, no wonder cats are cranky--not only do they have to hunt for their food, but they also can't enjoy a sweet dessert!"
Citation: Li X, Li W, Wang H, Cao J, Maehashi K, et al. (2005) Pseudogenization of a sweet-receptor gene accounts for cats' indifference toward sugar. PLoS Genet 1(1): e3.
Source:Public Library of Science
Page: 1 Related biology news :1
. Virologists make major step towards understanding the process of HIV infection2
. A new step towards an AIDS vaccine3
. New GM mosquito sexing technique is step towards malaria control, report scientists4
. Novel method reveals how menthol discovery could point towards new or improved pain therapies5
. Scientists make first step towards holy grail of crystallography6
. Salk researchers make fast strides towards understanding how our body controls walking7
. Thai spice helps cut blood sugar swings8
. Life-extending protein keeps blood sugar in check9
. Too much sugar not good for coral reefs10
. Darkness unveils vital metabolic fuel switch between sugar and fat11
. Scientists seek to unwrap the sweet mystery of the sugar coat on bacteria