**Acknowledgements**

*Canine Genetics, Health and Medicine*

earlier in life than females [16, 18, 20, 30, 106].

cardiovascular health and functions [112].

**5. Canines as a model for human cardiomyopathy**

disease for both canine and human benefit [123, 130].

and AF. There is some evidence that males are affected by DCM more often, or

Hypothyroidism has also been linked to increased DCM rates in some studies. For example Doberman Pinchsers with DCM were 2.26 times more likely to have or develop hypothyroidism [107], and suggestions to links between the two conditions was also proposed in two Great Dane individuals [108]. Some research has not necessarily shown a link between the two disorders [109–111], therefore there are still questions around links, especially causal ones. Although exact mechanisms, or indeed associations have yet to be determined, evidence does support that the thyroid hormones can have positive inotropic and chronotropic effects, and that under both experimental and in patients these may have important influences over

Current understanding of disease processes and treatments is based on studying affected individuals compared to unaffected individuals, along with the use of animal models of disease, cell lines, and computer simulations [113–119]. Natural models of disease allow researchers access to additional cases of disease without inducing disease and causing additional suffering, because the animals involved develop disease irrespective of involvement in a study. Therefore, a relevant resource for investigating health and disease is the companion animal population, within which dogs in particu-

The canine population overall is genetically heterogeneous, yet breeds are comparatively homogeneous which enhances their value as genetic models of disease [124]. Each breed of dog is a closed population and ancestry can typically be traced for many generations, often to the founding members of the breed [124–126]. This facilitates understanding the mode of inheritance of traits and diseases, and also restricts the amount of genetic diversity within a breed [34, 121, 125, 127]. Founder effects and subsequent inbreeding within pedigree dog breeds have led to differing allele frequencies between breeds, and some breeds are more prone to developing particular conditions than others [124, 128, 129]. This makes breeds with homologs of human conditions ideal for identifying potential genetic loci associated with

Many canine disease phenotypes can be closely matched to human disease phenotypes with similar disease progression, pathology, treatment options, and prognosis [78–80]. Indeed there are currently 383 potential canine models for human disease listed in OMIA (Online Mendelian Inheritance in Animals), greater than any other species [78, 79]. Dogs are typically treated as family members and so inhabit the same environment as their owners with the associated exposure to the same potential environmental toxins, including, for example, air pollution [131]. Pet dogs also frequently benefit from high quality medical care, such that illnesses are detected and treated promptly, similar to the human population [132]. These characteristics of the canine population make it a valuable resource as a model of human disease. Examples of diseases with homologies in humans and dogs include diabetes, cardiomyopathies, cancers, and eye diseases [79, 120, 123, 133, 134].

Diagnosis of disease is informed by patient symptoms, family history, medical testing, and in some cases genetic testing [135–137]. With greater understanding

lar are useful as natural models of the equivalent human disease [1, 120–123].

**30**

**6. Conclusions**

The authors gratefully acknowledge generous funding from the BBSRC University of Nottingham Doctoral Training Programme BB/J014508/1 and the School of Veterinary Medicine and Science. We would also like to thank The Wellcome Trust, The Academy of Medical Sciences for INSPIRE research funding. Catrin Rutland https://orcid.org/0000-0002-2009-4898.
