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Updated: May 24, 2026
07:57
Generation and Culture of Lingual Organoids Derived from Adult Mouse Taste Stem Cells
Published on: April 5, 2021
Major taste loss in carnivorous mammals
Peihua Jiang1, Jesusa Josue, Xia Li
1Monell Chemical Senses Center, Philadelphia, PA 19104, USA. pjiang@monell.org
Summary
Many meat-eating mammals, like cats, have lost their sweet taste receptor (Tas1r2) due to gene pseudogenization. This loss of taste receptor function is widespread and linked to specialized diets.
Area of Science:
- Sensory biology
- Evolutionary biology
- Genomics
Background:
- Mammalian taste perception relies on specific receptors: Type 1 taste receptors (Tas1r) for sweet and umami, and Tas2rs for bitter.
- Cats exhibit behavioral indifference to sweet tastes due to a non-functional Tas1r2 gene (pseudogenization).
Purpose of the Study:
- To investigate the prevalence and evolutionary basis of taste receptor gene pseudogenization across Carnivora.
- To correlate the loss of taste receptor function with dietary specializations in meat-eating mammals.
Main Methods:
- Sequencing of the Tas1r2 gene coding region in 12 Carnivora species.
- Analysis of gene sequences for mutations disrupting the open reading frame (ORF).
- Behavioral assays to assess sweet compound preference in selected species (Asian otter, spectacled bear).
Main Results:
- Seven of twelve non-feline Carnivora species, all obligate carnivores, independently evolved pseudogenized Tas1r2 genes.
- Relaxed purifying selection was observed in species with pseudogenized Tas1r2.
- The Asian otter (defective Tas1r2) showed no sweet preference, while the spectacled bear (intact Tas1r2) did.
- Pseudogenization of Tas1r1 and Tas1r3 was identified in sea lions and bottlenose dolphins, correlating with their whole-prey ingestion feeding behavior.
- Bottlenose dolphins also showed inactivation of all three Tas1rs and potentially bitter receptors.
Conclusions:
- Loss of sweet taste receptor (Tas1r2) function is common in obligate carnivores within the order Carnivora.
- Independent gene pseudogenization events in taste receptors are widespread in mammals.
- Taste receptor function loss is strongly associated with dietary specializations and feeding behaviors.
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