Richard Jorgensen

the well-known tendency of particular maladies to show breed-specificity can be used to infer likely sharing of descent of the causative alleles. As made clear in the volume under review, this is as true of major-gene diseases such as copper toxicosis and various retinopathies, as it is of the more complex and more prevalent cardiomyopathies, cancers, and dermatitis. Conduction of clinical trials is also much more difficult in humans. Human healthcare is expensive, and members of this species show a predilection toward law suits when things don't go quite right. By contrast, dog trials can be relatively quick to perform, study populations are fairly easily recruited, and it turns out the physiology and endocrinology of disease is often strikingly similar between the large mammals. Though not discussed in the volume, pharmacogenetics may get a boost from dogs, as refractoriness to drugs often displays similar levels as observed in humans — for example, veterinarians will tell you that approximately ten percent of epileptics are non-responsive to the commonly used pharmacological agents — and there is less of the litigious downside to mis-prediction. Gene therapy, too, has definite upsides in canines as various gene delivery approaches can be assessed in dogs for many treatable rare disorders that can actually be bred in study colonies. Why not mice? The simple answer is that most of the complex diseases we see in dogs are naturally occurring, as opposed to having been engineered into caged animals. Our pets share our toxicological and, to some extent, nutritional environment, and the similarities in the time of onset and etiology of so many of the major diseases is striking. It turns out, too, that our genomes are more similar at the level of gene content and sequence than those of rodents, even though rodents share a more recent common ancestor with Homo sapiens than do dogs. This is because of an accelerated rate of divergence in the smaller mammals. Nevertheless, many biomedical researchers, particularly those who serve on study sections, will point out that there are few remaining limits to gene discovery in humans, and what we really need is a model organism that we can manipulate genetically in order to test specific hypotheses. Transgenic dogs expressing GFP-tagged proteins aren't likely to be running around any time soon — though a dog with fluorescent green eyes may go down well with children — while biochemistry and molecular cell …