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Unique pattern of dietary adaptation in the dentition of Carnivora: its advantage and developmental origin

View Article: PubMed Central

ABSTRACT

Carnivora is a successful taxon in terms of dietary diversity. We investigated the dietary adaptations of carnivoran dentition and the developmental background of their dental diversity, which may have contributed to the success of the lineage. A developmental model was tested and extended to explain the unique variability and exceptional phenotypes observed in carnivoran dentition. Carnivorous mammalian orders exhibited two distinct patterns of dietary adaptation in molars and only Carnivora evolved novel variability, exhibiting a high correlation between relative molar size and the shape of the first molar. Studies of Bmp7-hetero-deficient mice, which may exhibit lower Bmp7 expression, suggested that Bmp7 has pleiotropic effects on these two dental traits. Its effects are consistent with the pattern of dietary adaptation observed in Carnivora, but not that observed in other carnivorous mammals. A molecular evolutionary analysis revealed that Bmp7 sequence evolved by natural selection during ursid evolution, suggesting that it plays an evolutionary role in the variation of carnivoran dentition. Using mouse experiments and a molecular evolutionary analysis, we extrapolated the causal mechanism of the hitherto enigmatic ursid dentition (larger M2 than M1 and M3). Our results demonstrate how carnivorans acquired novel dental variability that benefits their dietary divergence.

No MeSH data available.


Difference in relative molar sizes and M1 shape (relative trigonid and talonid size) between mice of different Usag-1 and Bmp7 genotypes. (a) Plots of M2/M1 versus M3/M1. Het, hetero-deficient; WT, wild-type. Plots are averages of each genotype and two-dimensional bars indicate the standard error. (b) Plots of M2/M1 versus tad/trd. Our results suggest that Bmp7 Het (i.e. a decrease in BMP7) generates larger M2/M1 and tad/trd scores. (c) Schematic illustration of mouse dentition for the integration of relative molar sizes and M1 shape caused by BMP7.
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RSPB20160375F3: Difference in relative molar sizes and M1 shape (relative trigonid and talonid size) between mice of different Usag-1 and Bmp7 genotypes. (a) Plots of M2/M1 versus M3/M1. Het, hetero-deficient; WT, wild-type. Plots are averages of each genotype and two-dimensional bars indicate the standard error. (b) Plots of M2/M1 versus tad/trd. Our results suggest that Bmp7 Het (i.e. a decrease in BMP7) generates larger M2/M1 and tad/trd scores. (c) Schematic illustration of mouse dentition for the integration of relative molar sizes and M1 shape caused by BMP7.

Mentions: For the dry skulls of F2 mice, the lower molar rows from the occlusal perspective were photographed, and the projected areas of the three molars (M1, M2 and M3) [39] as well as the trigonids (trd) and talonids (tad) of the M1 (the segmentation of the trigonid and talonid is shown in figure 3c) were measured. The general linear model (GLM) was applied to determine the effects of USAG-1, BMP7 and their statistical interactions based on the results of the double-deficient mouse phenotypes. After applying the Anderson–Daring normality test, the effects of USAG-1, BMP7 and their interaction on M2/M1, M3/M1 and tad/trd were examined using GLM implemented in Minitab 14 (Minitab, Inc., PA, USA).Figure 3.


Unique pattern of dietary adaptation in the dentition of Carnivora: its advantage and developmental origin
Difference in relative molar sizes and M1 shape (relative trigonid and talonid size) between mice of different Usag-1 and Bmp7 genotypes. (a) Plots of M2/M1 versus M3/M1. Het, hetero-deficient; WT, wild-type. Plots are averages of each genotype and two-dimensional bars indicate the standard error. (b) Plots of M2/M1 versus tad/trd. Our results suggest that Bmp7 Het (i.e. a decrease in BMP7) generates larger M2/M1 and tad/trd scores. (c) Schematic illustration of mouse dentition for the integration of relative molar sizes and M1 shape caused by BMP7.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920314&req=5

RSPB20160375F3: Difference in relative molar sizes and M1 shape (relative trigonid and talonid size) between mice of different Usag-1 and Bmp7 genotypes. (a) Plots of M2/M1 versus M3/M1. Het, hetero-deficient; WT, wild-type. Plots are averages of each genotype and two-dimensional bars indicate the standard error. (b) Plots of M2/M1 versus tad/trd. Our results suggest that Bmp7 Het (i.e. a decrease in BMP7) generates larger M2/M1 and tad/trd scores. (c) Schematic illustration of mouse dentition for the integration of relative molar sizes and M1 shape caused by BMP7.
Mentions: For the dry skulls of F2 mice, the lower molar rows from the occlusal perspective were photographed, and the projected areas of the three molars (M1, M2 and M3) [39] as well as the trigonids (trd) and talonids (tad) of the M1 (the segmentation of the trigonid and talonid is shown in figure 3c) were measured. The general linear model (GLM) was applied to determine the effects of USAG-1, BMP7 and their statistical interactions based on the results of the double-deficient mouse phenotypes. After applying the Anderson–Daring normality test, the effects of USAG-1, BMP7 and their interaction on M2/M1, M3/M1 and tad/trd were examined using GLM implemented in Minitab 14 (Minitab, Inc., PA, USA).Figure 3.

View Article: PubMed Central

ABSTRACT

Carnivora is a successful taxon in terms of dietary diversity. We investigated the dietary adaptations of carnivoran dentition and the developmental background of their dental diversity, which may have contributed to the success of the lineage. A developmental model was tested and extended to explain the unique variability and exceptional phenotypes observed in carnivoran dentition. Carnivorous mammalian orders exhibited two distinct patterns of dietary adaptation in molars and only Carnivora evolved novel variability, exhibiting a high correlation between relative molar size and the shape of the first molar. Studies of Bmp7-hetero-deficient mice, which may exhibit lower Bmp7 expression, suggested that Bmp7 has pleiotropic effects on these two dental traits. Its effects are consistent with the pattern of dietary adaptation observed in Carnivora, but not that observed in other carnivorous mammals. A molecular evolutionary analysis revealed that Bmp7 sequence evolved by natural selection during ursid evolution, suggesting that it plays an evolutionary role in the variation of carnivoran dentition. Using mouse experiments and a molecular evolutionary analysis, we extrapolated the causal mechanism of the hitherto enigmatic ursid dentition (larger M2 than M1 and M3). Our results demonstrate how carnivorans acquired novel dental variability that benefits their dietary divergence.

No MeSH data available.