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Mouse embryonic phenotyping by morphometric analysis of MR images.

Zamyadi M, Baghdadi L, Lerch JP, Bhattacharya S, Schneider JE, Henkelman RM, Sled JG - Physiol. Genomics (2010)

Bottom Line: Expressed in terms of organ volumes, heart and lung were larger in C57BL/6J embryos, while brain and liver were comparable in volume between strains.The positive relationship between organ size and embryo size was consistent for the two strains but differed by organ, with the brain and liver being the least variable.Together these findings suggest the power of this technique for detecting subtle phenotypic differences arising from mutated genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.

ABSTRACT
A new method is described for automatic detection of subtle morphological phenotypes in mouse embryos. Based on high-resolution magnetic resonance imaging scanning and nonlinear image alignment, this method is demonstrated by comparing the morphology of two inbred strains, C57BL/6J and 129Sv/S1ImJ, at 15.5 days postconception. Mouse embryo morphology was found to be highly amenable to this kind of analysis with very low levels (on average 110 μm) of residual anatomical variation within strains after linear differences in pose and scale are removed. Mapping of local size differences showed that C57BL/6J embryos were larger than 129Sv/S1ImJ embryos, although these differences were not uniformly distributed across the anatomy. Expressed in terms of organ volumes, heart and lung were larger in C57BL/6J embryos, while brain and liver were comparable in volume between strains. The positive relationship between organ size and embryo size was consistent for the two strains but differed by organ, with the brain and liver being the least variable. Together these findings suggest the power of this technique for detecting subtle phenotypic differences arising from mutated genes.

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Strain average images for 129S1/SvImJ (A) and C57BL/6J (B). Root mean square of the deformation magnitudes (RMSDM) images for 129S1/SvImJ (C) and C57BL/6J (D).
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Figure 3: Strain average images for 129S1/SvImJ (A) and C57BL/6J (B). Root mean square of the deformation magnitudes (RMSDM) images for 129S1/SvImJ (C) and C57BL/6J (D).

Mentions: The within-strain variation maps are shown for the two strains in Fig. 3, C and D. Comparing these positional variation maps to the average images (Fig. 3, A and B) highlights anatomical regions with greater positional variability such as the nose and the somites adjacent to the tail. It can be observed that the regions of highest variability (shown in red) are those most subject to postural differences such as the nose. Internal regions of the embryos and in particular the spine show the lowest variability (shown in blue). The mean RMSDM (± SD) was 118 ± 33 μm in the 129S1/SvImJ strain and 100 ± 27 μm in the C57BL/6J strain. These values are remarkably small compared with the 13 mm CRL typical of a 15.5 dpc embryo. Bootstrap analysis did not provide evidence that variability differed between the two strains.


Mouse embryonic phenotyping by morphometric analysis of MR images.

Zamyadi M, Baghdadi L, Lerch JP, Bhattacharya S, Schneider JE, Henkelman RM, Sled JG - Physiol. Genomics (2010)

Strain average images for 129S1/SvImJ (A) and C57BL/6J (B). Root mean square of the deformation magnitudes (RMSDM) images for 129S1/SvImJ (C) and C57BL/6J (D).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2957795&req=5

Figure 3: Strain average images for 129S1/SvImJ (A) and C57BL/6J (B). Root mean square of the deformation magnitudes (RMSDM) images for 129S1/SvImJ (C) and C57BL/6J (D).
Mentions: The within-strain variation maps are shown for the two strains in Fig. 3, C and D. Comparing these positional variation maps to the average images (Fig. 3, A and B) highlights anatomical regions with greater positional variability such as the nose and the somites adjacent to the tail. It can be observed that the regions of highest variability (shown in red) are those most subject to postural differences such as the nose. Internal regions of the embryos and in particular the spine show the lowest variability (shown in blue). The mean RMSDM (± SD) was 118 ± 33 μm in the 129S1/SvImJ strain and 100 ± 27 μm in the C57BL/6J strain. These values are remarkably small compared with the 13 mm CRL typical of a 15.5 dpc embryo. Bootstrap analysis did not provide evidence that variability differed between the two strains.

Bottom Line: Expressed in terms of organ volumes, heart and lung were larger in C57BL/6J embryos, while brain and liver were comparable in volume between strains.The positive relationship between organ size and embryo size was consistent for the two strains but differed by organ, with the brain and liver being the least variable.Together these findings suggest the power of this technique for detecting subtle phenotypic differences arising from mutated genes.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biophysics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada.

ABSTRACT
A new method is described for automatic detection of subtle morphological phenotypes in mouse embryos. Based on high-resolution magnetic resonance imaging scanning and nonlinear image alignment, this method is demonstrated by comparing the morphology of two inbred strains, C57BL/6J and 129Sv/S1ImJ, at 15.5 days postconception. Mouse embryo morphology was found to be highly amenable to this kind of analysis with very low levels (on average 110 μm) of residual anatomical variation within strains after linear differences in pose and scale are removed. Mapping of local size differences showed that C57BL/6J embryos were larger than 129Sv/S1ImJ embryos, although these differences were not uniformly distributed across the anatomy. Expressed in terms of organ volumes, heart and lung were larger in C57BL/6J embryos, while brain and liver were comparable in volume between strains. The positive relationship between organ size and embryo size was consistent for the two strains but differed by organ, with the brain and liver being the least variable. Together these findings suggest the power of this technique for detecting subtle phenotypic differences arising from mutated genes.

Show MeSH
Related in: MedlinePlus