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Genomic and genetic evidence for the loss of umami taste in bats.

Zhao H, Xu D, Zhang S, Zhang J - Genome Biol Evol (2011)

Bottom Line: Umami taste is responsible for sensing monosodium glutamate, nucleotide enhancers, and other amino acids that are appetitive to vertebrates and is one of the five basic tastes that also include sour, salty, sweet, and bitter.We found that Tas1r1 is absent, unamplifiable, or pseudogenized in each of the 31 species examined, including the genome sequences of two species, suggesting the loss of the umami taste in most, if not all, bats regardless of their food preferences.The puzzling absence of the umami taste in bats calls for a better understanding of the roles that this taste plays in the daily life of vertebrates.

View Article: PubMed Central - PubMed

ABSTRACT
Umami taste is responsible for sensing monosodium glutamate, nucleotide enhancers, and other amino acids that are appetitive to vertebrates and is one of the five basic tastes that also include sour, salty, sweet, and bitter. To study how ecological factors, especially diets, impact the evolution of the umami taste, we examined the umami taste receptor gene Tas1r1 in a phylogenetically diverse group of bats including fruit eaters, insect eaters, and blood feeders. We found that Tas1r1 is absent, unamplifiable, or pseudogenized in each of the 31 species examined, including the genome sequences of two species, suggesting the loss of the umami taste in most, if not all, bats regardless of their food preferences. Most strikingly, vampire bats have also lost the sweet taste receptor gene Tas1r2 and the gene required for both umami and sweet tastes (Tas1r3), being the first known mammalian group to lack two of the five tastes. The puzzling absence of the umami taste in bats calls for a better understanding of the roles that this taste plays in the daily life of vertebrates.

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Related in: MedlinePlus

The species tree of the bats examined for Tas1r taste receptor genes. The phylogeny and divergence times follow Teeling et al. (2005). Dietary preferences are indicated by various colors, and the functional status of the Tas1r genes is also indicated. Tas1r1 is umami specific, Tas1r2 is sweet specific, and Tas1r3 is used for both tastes. The Tas1r2 data are from Zhao, Zhou, et al. (2010), whereas those of Tas1r1 and Tas1r3 are from the present study.
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fig1: The species tree of the bats examined for Tas1r taste receptor genes. The phylogeny and divergence times follow Teeling et al. (2005). Dietary preferences are indicated by various colors, and the functional status of the Tas1r genes is also indicated. Tas1r1 is umami specific, Tas1r2 is sweet specific, and Tas1r3 is used for both tastes. The Tas1r2 data are from Zhao, Zhou, et al. (2010), whereas those of Tas1r1 and Tas1r3 are from the present study.

Mentions: We began by examining the two bat draft genome sequences at Ensembl (http://www.ensembl.org/). Mammalian Tas1r1 is encoded by six exons, of which the first five encode a long extracellular domain of this G-protein coupled receptor, whereas exon 6 encodes the remaining segment composed of the seven transmembrane domains, three extracellular loops, three intracellular loops, and the intracellular C-terminus. From the genome sequence of Pteropus vampyrus (fig. 1), commonly known as the large flying fox and one of the largest bats, we identified the complete exon 1 (182 bp), a partial exon 3 (137 bp), and a partial exon 6 (743 bp) of a single-copy Tas1r1 (supplementary fig. S1, Supplementary Material online). Although the open reading frame (ORF) is retained in exon 1 (despite a frame shifting deletion) and exon 3, it is disrupted in exon 6 by five insertions/deletions (indels) that result in four premature stop codons (supplementary fig. S1, Supplementary Material online), suggesting that Tas1r1 is a pseudogene in P. vampyrus.


Genomic and genetic evidence for the loss of umami taste in bats.

Zhao H, Xu D, Zhang S, Zhang J - Genome Biol Evol (2011)

The species tree of the bats examined for Tas1r taste receptor genes. The phylogeny and divergence times follow Teeling et al. (2005). Dietary preferences are indicated by various colors, and the functional status of the Tas1r genes is also indicated. Tas1r1 is umami specific, Tas1r2 is sweet specific, and Tas1r3 is used for both tastes. The Tas1r2 data are from Zhao, Zhou, et al. (2010), whereas those of Tas1r1 and Tas1r3 are from the present study.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3318850&req=5

fig1: The species tree of the bats examined for Tas1r taste receptor genes. The phylogeny and divergence times follow Teeling et al. (2005). Dietary preferences are indicated by various colors, and the functional status of the Tas1r genes is also indicated. Tas1r1 is umami specific, Tas1r2 is sweet specific, and Tas1r3 is used for both tastes. The Tas1r2 data are from Zhao, Zhou, et al. (2010), whereas those of Tas1r1 and Tas1r3 are from the present study.
Mentions: We began by examining the two bat draft genome sequences at Ensembl (http://www.ensembl.org/). Mammalian Tas1r1 is encoded by six exons, of which the first five encode a long extracellular domain of this G-protein coupled receptor, whereas exon 6 encodes the remaining segment composed of the seven transmembrane domains, three extracellular loops, three intracellular loops, and the intracellular C-terminus. From the genome sequence of Pteropus vampyrus (fig. 1), commonly known as the large flying fox and one of the largest bats, we identified the complete exon 1 (182 bp), a partial exon 3 (137 bp), and a partial exon 6 (743 bp) of a single-copy Tas1r1 (supplementary fig. S1, Supplementary Material online). Although the open reading frame (ORF) is retained in exon 1 (despite a frame shifting deletion) and exon 3, it is disrupted in exon 6 by five insertions/deletions (indels) that result in four premature stop codons (supplementary fig. S1, Supplementary Material online), suggesting that Tas1r1 is a pseudogene in P. vampyrus.

Bottom Line: Umami taste is responsible for sensing monosodium glutamate, nucleotide enhancers, and other amino acids that are appetitive to vertebrates and is one of the five basic tastes that also include sour, salty, sweet, and bitter.We found that Tas1r1 is absent, unamplifiable, or pseudogenized in each of the 31 species examined, including the genome sequences of two species, suggesting the loss of the umami taste in most, if not all, bats regardless of their food preferences.The puzzling absence of the umami taste in bats calls for a better understanding of the roles that this taste plays in the daily life of vertebrates.

View Article: PubMed Central - PubMed

ABSTRACT
Umami taste is responsible for sensing monosodium glutamate, nucleotide enhancers, and other amino acids that are appetitive to vertebrates and is one of the five basic tastes that also include sour, salty, sweet, and bitter. To study how ecological factors, especially diets, impact the evolution of the umami taste, we examined the umami taste receptor gene Tas1r1 in a phylogenetically diverse group of bats including fruit eaters, insect eaters, and blood feeders. We found that Tas1r1 is absent, unamplifiable, or pseudogenized in each of the 31 species examined, including the genome sequences of two species, suggesting the loss of the umami taste in most, if not all, bats regardless of their food preferences. Most strikingly, vampire bats have also lost the sweet taste receptor gene Tas1r2 and the gene required for both umami and sweet tastes (Tas1r3), being the first known mammalian group to lack two of the five tastes. The puzzling absence of the umami taste in bats calls for a better understanding of the roles that this taste plays in the daily life of vertebrates.

Show MeSH
Related in: MedlinePlus