Phenotypic and Genetic Analysis of the Leopard Complex Spotting in Noriker Horses.

Genetic analyses of coat colors are frequently restricted to subjectively categorized phenotype information. The aim of this study was to develop a method to numerically quantify the variability of leopard complex (LP) spotting phenotypes introducing tools from image analysis. Generalized Procrustes analysis eliminates systematic errors due to imaging process. The binarization of normalized images and the application of principal component analysis (PCA) on the derived pixel matrices, transform pixel information into numerical data space. We applied these methods on 90 images to ascertain the specific leopard patterns within the Noriker breed. Furthermore, we genotyped a representative sample of 191 Noriker horses for the known LP spotting associated loci. Ninety-seven percentage of the genotyped leopard spotted horses were heterozygous for LP and had at least one copy of the PATN1 allele. However, the remaining pattern variation was great, indicating other genetic factors influencing the expression of LP spotting. Based upon this data, we estimated effect sizes of the modifier PATN1, and additional factors including sex, age, base color, and spotting phenotype of parents. The PCA of the pixel matrix resulted in 2 significant components accounting for 51% of the variation. Applying a linear model, we identified significant effects for age groups and base color on the first and second components, while for sex and parents' LP phenotype significant effects were found on 4 additional components.

Measuring fat mass in body equivalent materials using an RF resonant cavity.

PURPOSE: Provide a proof of concept for the potential of using a novel RF resonant cavity device for accurately and repeatedly measuring fat and fat-free masses in phantom infants. MATERIALS & METHODS: Design, construct, and characterize an RF resonant cavity with dimensions compatible to holding an infant. The cavity was characterized using spherical phantoms of 0%fat, 50% fat, and 100% fat to empirically calibrate shifts in resonant frequency. The phantoms were constructed using emulsions of bovine lard, water, and dish soap inside spherical containers which do not interact with the electric field. The calibration phantoms were compared with a phantom of a test sample to assess the ability of the resonant cavity perturbation technique for measuring body composition. RESULTS: Phantoms of distinct %fat (0%, 50%, and 100%) were used to calibrate the resonant cavity for measuring body composition. The calibration phantoms were used to create calibration lines of unique %fat and were compared to a 475-mL sample of unknown %fat as a measure of how accurate the resonant cavity technique is for measuring body composition. CONCLUSION: A 475 mL test sample was used to examine the robustness of the RCP technique. The sample was 25% fat and had a fat mass of ( 116.67 ± 0.96 ) g. The measured fat mass from the RCP technique was 114.30 ± 0.98  g, or a 2% difference. The resonant cavity perturbation technique provides an accurate and repeatable measurement of fat mass in spherical phantoms and suggests the technology might be an effective obesity research tool for infants. Future studies will focus on extending the work to more complex anthropomorphic shapes.