Inter-population shape differentiation of the first upper and lower molars.

<p>(A) Upper molars; (B) lower molars. Symbols are average values per geographic groups ± standard deviation. Shape axes correspond to the first two principal components describing variation of the Fourier coefficients of the outline analysis. PC1 corresponds to the V1 vector of the total sample. Shape changes along the first axes are visualized by reconstructed outlines corresponding to three times the unit variation along V1.</p

Size and shape of the first upper and lower molars in the mainland and Corsican sample and some populations displaying size increases: Iran, Denmark and Marion Island.

<p>A sample of the pygmy mouse <i>Nannomys mattheyi</i> is included. (A). Tooth length distribution per population, upper molar above and lower molar below. Large symbols correspond to teeth shown in C. (B). Size – shape relationship between these populations. Shape is estimated by a new synthetic axis including the additional populations. It is highly correlated to the total axis previously considered in the study (R = 0.999 for UM1 and LM1). Large UM1s are clearly shifted in shape, whereas this is not the case for the LM1. (C). Examples of UM1s displaying a prestyle in the different populations, with their lower counterpart.</p

Sampling area and illustration of the tooth variation.

<p>(A) Localization of the sampling localities, with colors corresponding to the mainland and the different islands. Pooling of several localities in larger geographic groups is indicated by dotted lines. (B) Example of upper (top panel) and lower (bottom panel) molars of the house mouse (<i>Mus musculus domesticus</i>) in mainland Southern France (Montpellier), Corsica and the islet Piana. The arrow points to the prestyle on the first upper molar from Piana.</p

Main directions of shape changes in Gardouch (blue) and Fango (red).

<p>(A) main intra-population variation, (B) intra-population co-variation and (C) allometry. (A) Shape changes along the direction of greatest variance (V1) corresponding to ±3×V1. (B) Co-variation between the first upper and first lower molars based on Partial Least Squares analyses corresponding to ±0.03 PLS1. (C) Allometric change in molar shape corresponding to a 20% size increase, based on the multivariate regression between size and shape.</p

Geographic groups (with localities of trapping) documenting the variation within the house mouse <i>Mus musculus domesticus</i> (<i>M.m.d.</i>), and the additional sample documenting the pygmy mouse <i>Nannomys mattheyi</i>.

<p>Material housed in the collection of the Centre de Biologie et Gestion des Populations (CBGP, Baillarguet, France), of the Institut des Sciences de l'Evolution de Montpellier (ISEM, Montpellier, France) and of the Museum National d'Histoire Naturelle (MNHN, Paris, France). Number of teeth measured: UM1 (first upper molar); LM1: first lower molar.</p

Upper tooth rows; wild-type morphology and morphotypes defined among <i>Eda^Ta</i> and <i>Edar^dl-J</i> mutant mice.

<p>A: WT morphology, B: <i>Edar^dl-j/+</i> morphology; C: morphotype Ta He0; D: morphotype Ta He1; E: morphotype Ta He2; F: morphotype Ta He3; G: morphotype Ta He4; H: <i>Edar^dl-j</i> morphology; I: morphotype <i>Eda^Ta</i> Ho1; J: morphotype <i>Eda^Ta</i> Ho2. The proportions indicated below the morphotypes are the occurrence frequency of the morphotypes. Images are obtained using X-ray synchrotron microtomography. Tooth orientation: M: mesial, D: distal, V: vestibular, and L: lingual. Scale bar: 1 mm. The structures indicated by arrows and asterisk are discussed in the main text.</p

Additional file 1: of Transcriptomic signatures shaped by cell proportions shed light on comparative developmental biology

Supplementary figures S1-S7 and supplementary text. Figure S1. First axis of the lower-specific and upper-specific PCAs orders samples with time. Figure S2. Gene ontology analysis of the genes robustly assigned to one of the ten clusters obtained for lower and upper molar. Figure S3. Mesenchyme proportion estimated using deconvolutions with markers based on microarray data. Figure S4. Mesenchyme proportion are always larger in upper molar as measured from 3D reconstructions of dissected tooth germs. Figure S5. Models of cusp patterning and expansion in the lower and upper molars. Figure S6. Heterochrony signals are visible in the transcriptomes of each tissue compartment. Figure S7. In a limb development dataset, PCA1 coordinates correlate with proportions of chondrocytes estimated by deconvolution (see supplementary text). Supplementary text. Time signal and heterochrony in limb development can be interpreted alongside with estimation of the proportion of differentiated cell types. (PDF 3938 kb

Lower tooth rows; wild-type morphology and morphotypes defined among <i>Eda^Ta</i> and <i>Edar^dl-J</i> mutant mice.

<p>A: WT morphology; B: <i>Edar^dl-J/+</i> morphology; C–D: <i>Edar^dl-j</i> morphotype Dl1, E: <i>Edar^dl-j</i> morphotype Dl2, F–G: <i>Edar^dl-j</i> morphotype Dl3, H: <i>Edar^dl-j</i> morphotype Dl4, I–K: <i>Eda^Ta</i> morphotypes, L: <i>Eda^Ta</i> morphotype Ia, M: <i>Eda^Ta</i> morphotype Ib, N: <i>Eda^Ta</i> morphotype Ic, O: <i>Eda^Ta</i> morphotype IIa, P: <i>Eda^Ta</i> morphotype IIb. The proportions indicated below the morphotypes are the occurrence frequency of the morphotypes. Images of <i>Edar</i>^dl-J mice are obtained using X-ray synchrotron microtomography. Images of <i>Eda</i>^Ta mice are obtained by photography and are taken from Kristenova et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004985#pone.0004985-Kristenova1" target="_blank">[10]</a> and Peterkova et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004985#pone.0004985-Peterkova1" target="_blank">[30]</a>. Same orientation as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004985#pone-0004985-g001" target="_blank">Fig. 1</a>. The structures indicated by arrows are discussed in the main text.</p

Size of the cheek teeth of Wild-type, Downless and Tabby heterozygous (+/−) and homozygous (−/−) mice.

<p>A. Upper cheek teeth. Dark grey: T¹, light grey: T², white: T³, and hatched: T⁴. B. Lower cheek teeth. Dark grey: T₁, light grey: T₂, white: T₃, and hatched: T₄. Black bars indicate the standard-deviation of the mean. WT: Wild-type mice, dl-J/+: <i>Edar^dl-J/+</i>, Ta/+: <i>Eda^Ta/+</i>, dl-J: <i>Edar^dl-J</i>, Ta: <i>Eda^Ta</i>. The arrows indicate the statistical size comparison between morphologically close morphotypes, the three circles on each arrow represent from top to bottom the first, second and third cheek teeth, a grey-filled circle indicates a statistically significant difference in size between the two considered teeth according to a Wilcoxon rank-test at p = 0.05 threshold value, a white circle indicates the absence of statistical difference. Morphotypes that appear to be obviously different on the plot were found to have statistically significant differences.</p