Commonalities and evolutionary divergences of mandible shape ontogenies in rodents

2021 ◽  
Vol 34 (10) ◽  
pp. 1637-1652
Author(s):  
Morgane Dubied ◽  
Sophie Montuire ◽  
Nicolas Navarro
Keyword(s):  
Mandible Shape

scholarly journals Integration and Modularity of Quantitative Trait Locus Effects on Geometric Shape in the Mouse Mandible

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1909-1921
Author(s):  
Christian Peter Klingenberg ◽  
Larry J Leamy ◽  
James M Cheverud
Keyword(s):  
Quantitative Trait ◽  
Parametric Bootstrap ◽  
Interval Mapping ◽  
Procrustes Analysis ◽  
Bootstrap Test ◽  
Mandible Shape ◽  
Trait Locus ◽  
F2 Generation ◽  
Analysis Interval ◽  
Qtl Effects

Abstract The mouse mandible has long served as a model system for complex morphological structures. Here we use new methodology based on geometric morphometrics to test the hypothesis that the mandible consists of two main modules, the alveolar region and the ascending ramus, and that this modularity is reflected in the effects of quantitative trait loci (QTL). The shape of each mandible was analyzed by the positions of 16 morphological landmarks and these data were analyzed using Procrustes analysis. Interval mapping in the F2 generation from intercrosses of the LG/J and SM/J strains revealed 33 QTL affecting mandible shape. The QTL effects corresponded to a variety of shape changes, but ordination or a parametric bootstrap test of clustering did not reveal any distinct groups of QTL that would affect primarily one module or the other. The correlations of landmark positions between the two modules tended to be lower than the correlations between arbitrary subsets of landmarks, indicating that the modules were relatively independent of each other and confirming the hypothesized location of the boundary between them. While these results are in agreement with the hypothesis of modularity, they also underscore that modularity is a question of the relative degrees to which QTL contribute to different traits, rather than a question of discrete sets of QTL contributing to discrete sets of traits.

scholarly journals Robust and Accurate Mandible Segmentation on Dental CBCT Scans Affected by Metal Artifacts Using a Prior Shape Model

2021 ◽  
Vol 11 (5) ◽  
pp. 364
Author(s):  
Bingjiang Qiu ◽  
Hylke van der van der Wel ◽  
Joep Kraeima ◽  
Haye Hendrik Glas ◽  
Jiapan Guo ◽  
...  
Keyword(s):  
State Of The Art ◽  
Maxillofacial Surgery ◽  
Cone Beam ◽  
Oral And Maxillofacial Surgery ◽  
Metal Artifacts ◽  
Shape Model ◽  
High Attenuation ◽  
Mandible Shape ◽  
Prior Shape ◽  
Segmentation Models

Accurate mandible segmentation is significant in the field of maxillofacial surgery to guide clinical diagnosis and treatment and develop appropriate surgical plans. In particular, cone-beam computed tomography (CBCT) images with metal parts, such as those used in oral and maxillofacial surgery (OMFS), often have susceptibilities when metal artifacts are present such as weak and blurred boundaries caused by a high-attenuation material and a low radiation dose in image acquisition. To overcome this problem, this paper proposes a novel deep learning-based approach (SASeg) for automated mandible segmentation that perceives overall mandible anatomical knowledge. SASeg utilizes a prior shape feature extractor (PSFE) module based on a mean mandible shape, and recurrent connections maintain the continuity structure of the mandible. The effectiveness of the proposed network is substantiated on a dental CBCT dataset from orthodontic treatment containing 59 patients. The experiments show that the proposed SASeg can be easily used to improve the prediction accuracy in a dental CBCT dataset corrupted by metal artifacts. In addition, the experimental results on the PDDCA dataset demonstrate that, compared with the state-of-the-art mandible segmentation models, our proposed SASeg can achieve better segmentation performance.

Mandible shape modeling using the second eigenfunction of the Laplace-Beltrami operator

2011 ◽  
Author(s):  
Seongho Seo ◽  
Moo K. Chung ◽  
Brian J. Whyms ◽  
Houri K. Vorperian
Keyword(s):  
Beltrami Operator ◽  
Shape Modeling ◽  
Mandible Shape

scholarly journals Morphometric models for estimating bite force in Mus and Rattus: mandible shape and size perform better than lever-arm ratios

2019 ◽  
Vol 222 (12) ◽  
pp. jeb204867 ◽  
Author(s):  
Samuel Ginot ◽  
Anthony Herrel ◽  
Julien Claude ◽  
Lionel Hautier
Keyword(s):  
Bite Force ◽  
Lever Arm ◽  
Mandible Shape ◽  
Shape And Size ◽  
Better Than

Mandible shape and dwarfism in squirrels (Mammalia, Rodentia): interaction of allometry and adaptation

2009 ◽  
Vol 96 (6) ◽  
pp. 725-730 ◽  
Author(s):  
Lionel Hautier ◽  
Pierre-Henri Fabre ◽  
Jacques Michaux
Keyword(s):  
Mandible Shape

Geometric morphometrics of mandibular shape in the dwarf fat-tailed jerboa: relevancy for trinomial taxonomy

2020 ◽  
Author(s):  
Boris Kryštufek ◽  
Georgy Shenbrot ◽  
Tina Klenovšek ◽  
Franc Janžekovič
Keyword(s):  
Spatial Variation ◽  
Geometric Morphometrics ◽  
Independent Study ◽  
Glans Penis ◽  
Environmental Pressure ◽  
Taxonomic Information ◽  
Mandible Shape ◽  
Mandibular Morphology ◽  
The One ◽  
Null Expectation

Abstract We explore the pattern of spatial variation in mandibular morphology in relation to subspecific taxonomy in the dwarf fat-tailed jerboa, Pygeretmus pumilio. The unguided k-means clustering on mandible shape scores, partitioned populations into two clusters, corresponding to western and eastern populations. These clusters nearly perfectly matched the two subspecies groups (pumilio and potanini groups) recognized in an independent study based on the morphology of the glans penis. The mandible, although under environmental pressure, has retained a sufficient amount of taxonomic information to retrieve grouping closely resembling the one derived from a sexually selective trait. We recommend morphometrics of the mandible as a routine step in addressing variations in mammals at species and subspecies levels. We also stress the advantage of unsupervised k-clustering in testing null expectation in subspecies taxonomies. However, the power of this approach has its limitations and in our analysis, the k-clustering failed to retrieve subspecies in the potanini group.

scholarly journals Morphological variability of the mandible shape in the common vole Microtus arvalis (Rodentia, Arvicolidae) hybrid zone

2019 ◽  
Vol 488 (5) ◽  
pp. 576-580
Author(s):  
T. A. Mironova ◽  
V. B. Sycheva ◽  
A. A. Martynov ◽  
A. R. Gromov ◽  
D. S. Kostin ◽  
...  
Keyword(s):  
Hybrid Zone ◽  
Horizontal Plane ◽  
Morphological Variability ◽  
Common Vole ◽  
Microtus Arvalis ◽  
Geometric Morphometry ◽  
Mandible Shape ◽  
The Common ◽  
First Time ◽  
Microtus Obscurus

For the first time, the analysis of the mandible shape in semispecies of common vole (Microtus arvalis) from the hybrid zone was carried out using geometric morphometry methods. High morphological variability of hybrids that were closer to the parent form Microtus obscurus than to M. arvalis was found. The main trends in the shape of the mandible, which locate mainly in the horizontal plane, are revealed.

scholarly journals Bite force and its relationship to jaw shape in domestic dogs

2020 ◽  
Vol 223 (16) ◽  
pp. jeb224352 ◽  
Author(s):  
Colline Brassard ◽  
Marilaine Merlin ◽  
Claude Guintard ◽  
Elodie Monchâtre-Leroy ◽  
Jacques Barrat ◽  
...  
Keyword(s):  
Morphological Variability ◽  
Three Dimensional ◽  
Biomechanical Model ◽  
Bite Force ◽  
Domestic Dogs ◽  
Temporal Muscle ◽  
Molar Teeth ◽  
Mandible Shape ◽  
Force Variation

ABSTRACTPrevious studies based on two-dimensional methods have suggested that the great morphological variability of cranial shape in domestic dogs has impacted bite performance. Here, we used a three-dimensional biomechanical model based on dissection data to estimate the bite force of 47 dogs of various breeds at several bite points and gape angles. In vivo bite force for three Belgian shepherd dogs was used to validate our model. We then used three-dimensional geometric morphometrics to investigate the drivers of bite force variation and to describe the relationships between the overall shape of the jaws and bite force. The model output shows that bite force is rather variable in dogs and that dogs bite harder on the molar teeth and at lower gape angles. Half of the bite force is determined by the temporal muscle. Bite force also increased with size, and brachycephalic dogs showed higher bite forces for their size than mesocephalic dogs. We obtained significant covariation between the shape of the upper or lower jaw and absolute or residual bite force. Our results demonstrate that domestication has not resulted in a disruption of the functional links in the jaw system in dogs and that mandible shape is a good predictor of bite force.

scholarly journals Masticatory system integration in a commensal canid: interrelationships between bones, muscles and bite force in the red fox

2021 ◽  
Vol 224 (5) ◽  
Author(s):  
Colline Brassard ◽  
Marilaine Merlin ◽  
Elodie Monchâtre-Leroy ◽  
Claude Guintard ◽  
Jacques Barrat ◽  
...  
Keyword(s):  
Red Fox ◽  
Bite Force ◽  
Similar Amount ◽  
Canis Lupus Familiaris ◽  
Cross Sectional ◽  
Domestic Species ◽  
Mandible Shape ◽  
The Impact ◽  
Strong Relationships

ABSTRACT The jaw system in canids is essential for defence and prey acquisition. However, how it varies in wild species in comparison with domestic species remains poorly understood, yet is of interest in terms of understanding the impact of artificial selection. Here, we explored the variability and interrelationships between the upper and lower jaws, muscle architecture and bite force in the red fox (Vulpes vulpes). We performed dissections and used 3D geometric morphometric approaches to quantify jaw shape in 68 foxes. We used a static lever model and bite force estimates were compared with in vivo measurements of 10 silver foxes. Our results show strong relationships exist between cranial and mandible shape, and between cranial or mandible shape on the one hand and muscles or estimated bite force on the other hand, confirming the strong integration of the bony and muscular components of the jaw system. These strong relationships are strongly driven by size. The functional links between shape and estimated bite force are stronger for the mandible, which probably reflects its greater specialisation towards biting. We then compared our results with data previously obtained for dogs (Canis lupus familiaris) to investigate the effect of domestication. Foxes and dogs differ in skull shape and muscle physiological cross-sectional area (PCSA). They show a similar amount of morphological variation in muscle PCSA, but foxes show lower variation in cranial and mandible shape. Interestingly, the patterns of covariation are not stronger in foxes than in dogs, suggesting that domestication did not lead to a disruption of the functional links of the jaw system.

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