Genetics Study on Inbreeding in Dogs

The University of California has presented a large study on inbreeding in dogs and its consequences for health. What emerged is alarming in places – and should give anyone who owns or wants to buy a dog food for thought.

High Inbreeding Coefficient in Dogs

For the investigation, the research team evaluated genetic samples from almost 50,000 dogs. The focus was on the question of how similar the DNA of the individual animals is. The result: The so-called inbreeding coefficient averaged 0.24 – i.e., around 25 percent. This is more than many would expect.

What does this value mean concretely? The inbreeding coefficient measures the degree of relatedness between individuals – more precisely, how often exactly the same genes occur in two animals. A value of 0 means: no relatedness. The closer the value gets to 1, the more closely related the animals are genetically – 1 would correspond to genetically identical twins. A value of 0.24 is roughly at the level one would expect with siblings. That says a lot.

Possible Consequences of High Inbreeding Coefficients

The study provided clear indications that a high degree of inbreeding can burden the health of dogs on several levels:

• Higher susceptibility to hereditary diseases
• Weakened immune system – and thus also greater susceptibility to other diseases
• Smaller litters
• Lower survival rates for puppies
• Malformations of body parts or internal organs

None of these points is an inevitable fate – but the accumulation of such risks in a breed should not leave anyone indifferent.

How does inbreeding in dogs come about in the first place?

Interestingly: In the wild, animals instinctively avoid mating with close relatives. The problem therefore does not arise on its own – it is man-made.

In organised dog breeding, it is often about consolidating very specific traits: the coat colour, a typical body shape, certain character traits. If a male dog or female dog has proven to be particularly «typical», it quickly comes to pass that this animal is used for breeding again and again – and eventually also mated with its own offspring. What initially sounds like targeted selection is simply inbreeding in practice.

In addition: Clear legal regulations are lacking in most countries. Breeders who deliberately mate related animals often operate in a legal grey area – without anyone being able to seriously prohibit them from doing so.

Demand determines supply

As uncomfortable as it is: Part of the problem lies with the buyer. Many of the breed standards criticised today did not just come about – they were shaped by the ideas people have of a «beautiful» dog. Extremely short noses, overbred body shapes, particularly small stature – all this found buyers, so it was bred.

Anyone looking for a dog does themselves and the animal a favour if they focus less on appearance and look more at what truly corresponds to the dog: species-appropriate nature, robust health, no exaggerated breeding traits.

You can find the full results of the study «The Influence of Inbreeding, Size and Morphology on Health in Dog Breeds» here.