Validation through a comparison of physical examination and DNA test results: OLFML3 case study

Objective

To investigate the usefulness of predicting the presence of a genetic mutation in a population based on data arising from physical examinations and its use as a validator of grading schemes.

Methods

We employ an inference algorithm adjusted for large scale application and apply it to the particular case of Olfactomedin Like 3 (OLFML3) gene in the Border Collie, where essentially independent results of DNA test and physical exam exist, to find out to what extent the two predictions agree and highlight systematic discrepancies.

Results

Large scale inference over a population of 243,752 Border Collie dogs is combined with statistical data mining techniques on available DNA test and physical exam results corresponding to the OLFML3 gene and physical gonioscopy. Aside from validating the inference technique, the results are two fold: (1) sources of possible errors are identified indicating potential revisions of the physical examination grading scheme, and (2) the inference is found to approach close values within a short distance (1 or 2 steps away from a tested animal) based on physical examinations alone, supporting the usefulness of predictions based solely on the results of a physical exam.

Conclusion

A systematic comparison of the inference results based on a physical examination and on DNA tests highlights any problems with the grading scheme used for the physical examinations. The proximity of physical examination and DNA based inference suggests that the method could be employed to select the most informative subjects to explore when a method of inheritance of a condition is suspected but only a physical examination is possible.