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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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Related in: MedlinePlus

Scatter plot of normalized organ volume vs. normalized crown-to-rump length (n = 37) for each organ. Best-fit linear regression lines with 95% confidence intervals shaded are also plotted.
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Figure 5: Scatter plot of normalized organ volume vs. normalized crown-to-rump length (n = 37) for each organ. Best-fit linear regression lines with 95% confidence intervals shaded are also plotted.

Mentions: The relationship between organ volumes and embryo size is presented in Fig. 5. Computing an organ volume and a CRL normalized by the mean for the given strain allowed the relationship between organ volumes and embryo size to be compared for the different organs. As the regression slopes did not significantly differ between strains, all 37 embryos were pooled for this analysis following normalization by the mean organ volumes for each strain. Organ volumes were found to be strongly correlated with CRL (R2 > 0.52 for all organs, P < 0.0001). The regression slopes were 2.6 (lung), 2.0 (liver), 1.5 (heart), and 1.1 (brain), respectively. An analysis of variance in the regression slopes revealed significant differences (P = 0.002) between organs.


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)

Scatter plot of normalized organ volume vs. normalized crown-to-rump length (n = 37) for each organ. Best-fit linear regression lines with 95% confidence intervals shaded are also plotted.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Scatter plot of normalized organ volume vs. normalized crown-to-rump length (n = 37) for each organ. Best-fit linear regression lines with 95% confidence intervals shaded are also plotted.
Mentions: The relationship between organ volumes and embryo size is presented in Fig. 5. Computing an organ volume and a CRL normalized by the mean for the given strain allowed the relationship between organ volumes and embryo size to be compared for the different organs. As the regression slopes did not significantly differ between strains, all 37 embryos were pooled for this analysis following normalization by the mean organ volumes for each strain. Organ volumes were found to be strongly correlated with CRL (R2 > 0.52 for all organs, P < 0.0001). The regression slopes were 2.6 (lung), 2.0 (liver), 1.5 (heart), and 1.1 (brain), respectively. An analysis of variance in the regression slopes revealed significant differences (P = 0.002) between organs.

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