Breeding closely related dogs is known as interbreeding. Breeding dogs too closely related isn’t recommended because it can cause genetic issues. Despite the risks, there are benefits as well. In fact, it’s how our modern day dog breeds were created.

It’s a complex subject. Some breeders will breed closely related dogs to enhance desirable traits, while some institutions prohibit the practice. 

Can you breed dogs with different dads but the same mom?

Dogs with different dads but the same mother are half siblings. Interbreeding is actually the cornerstone of purebred lines of any animal. 

In today’s culture, we wouldn’t dream of marrying or mating with anyone closely related to us. However, in ancient times, it was quite common. 

As our understanding of genetics has increased, we have a clearer picture of the consequences of interbreeding. This includes both risks and benefits. 

Homogeneous Genes

Each animal has two sets of genes, one from the father and one from the mother. When closely related dogs are bred, it increases the chance that the offspring will have two identical copies of some genes. 

This has positive and negative effects. It can be an advantage in selective breeding, because it strengthens certain desirable genes, and increases the odds of the gene being passed down. 

However, this also increases the risk of undesirable genes. PRA (Progressive Retinal Atrophy), is one example. It causes progressive blindness. A dog with one PRA gene will have normal vision. However, a dog with two PRA genes will develop the disease. 

Inbreeding Coefficient

The inbreeding coefficient is used to determine the likelihood both copies of any given gene originate from a single ancestor and are homogeneous. 

An inbreeding coefficient of 0 is the result of two purebred dogs from different breeds. They will share a common ancestor in the very distant past. A coefficient of 100 would be the result of breeding brother and sister for many generations, and is a very rare occurrence. 

Mating a brother and sister from parents that are unrelated gives an inbreeding coefficient of 50%. Breeding a father and daughter or mother and son gives a coefficient of 25% if there is no interbreeding in previous generations. 

A mating between cousins results in a coefficient of only 6%, assuming no other interbreeding occured in recent generations. 

When considering other related breedings in the family line, you’ll need to go back five generations. You can learn more about inbreeding coefficients by using the program GENES.

Interbreeding Pros and Cons

Interbreeding can be used to fix certain genetic traits into a breed or line. Show dogs, for example, are highly sought after as studs, because they are likely to pass on their winning genetic traits. 

However, close interbreeding over generations causes significant issues. These effects can be observed in wolf packs. Members of the pack stay together and interbreed.  Over time, they become very genetically similar. 

They become more susceptible to diseases because they don’t have the genes to resist them. In extreme cases, litters become much smaller and there’s a high infant mortality rate. Extremely interbred animals can also become sterile. 

Average Breeding Coefficient

The average breeding coefficient will vary significantly between breeds. Most breeds will average between 6-12%. A breeding coefficient over 5 increases the risk of undesirable traits slightly. At 10%, the risk is more significant. When the coefficient is over 10% the risk is greatly increased. 

When deciding whether or not to breed dogs, it’s recommended that the coefficient is less than or equal to the breed average. 

Most registries won’t register dogs with a very high degree of inbreeding. For example, the Kennel Club will register dogs with a higher than average breeding coefficient. However, they will not register puppies from a  father and daughter, mother and son, or brother and sister.

Half Brother and Sister Breeding

A half brother and sister mating will produce puppies with an inbreeding coefficient of 12.5%, assuming there was no interbreeding in previous generations. If the line was inbred in recent generations, the coefficient will be higher. 

This coefficient is higher than recommended under most circumstances. In short, it would be preferable to breed dogs that are not so closely related. If there is no other interbreeding in recent generations, you may choose to breed them. However, their offspring should be bred with an unrelated line to increase gene variation. 

It can be difficult to register half sibling offspring with the Kennel Club. However, the largest US registry, the AKC, has no prohibition on inbreeding. 

Reasons to Choose Half-Sibling Inbreeding

There are situations when inbreeding is a reasonable course of action. If the two parents are proven to be disease free and carry desirable traits, it can be desirable to breed them to pass on these traits. 

Breeding half siblings is a better option than closer inbreeding. Breeding mothers and sons, fathers and daughters, or full siblings carries a higher risk of deleterious genes than half siblings. 

Genetic Tests Before Breeding

Performing genetic testing before breeding can reduce the risk of passing on defective genes. 40% of purebred dogs have genetic issues that will cause a health condition at some point in their lives. 

Genetic testing can reveal genetic defects and predispositions to certain diseases and health conditions. It should be considered when determining which dogs to breed. If you breed dogs with genetic defects, there’s a chance they will pass the defect on to their offspring. 

How Breeds are Created

All dogs descended from one lineage of wolves. This occurred 1,000s of years ago, but most dog breeds are recent creations. Dog breeds are essentially created by interbreeding. 

Selective breeding, or breeding certain dogs with desired traits in an attempt to make more dogs with those traits, has been around since we first domesticated our furry companions. 

However, in the 19th century, it began to develop into the breeds we know and love today. Breeders began breeding dogs for many different traits, both physical and behavioral. 

Today the AKC classifies breeds into one of five groups, and recognizes 167 breeds. Other organizations recognize 300 to 400 different breeds. 

Each of these breeds was created by breeding a small number of dogs and their offspring. If you are creating the golden retriever breed, for example, your goal would be to breed retrievers with yellow coats. The amount of these dogs would be limited in the beginning, so you would need to breed related dogs fairly regularly. 

This interbreeding is how breed specific genetic diseases developed. Rottweilers are prone to bone cancer. Springer Spaniels are at a high risk for epilepsy. German Shepards commonly develop hip dysplasia. This occurs because these genes were propagated in the breed due to a lack of genetic diversity. 

Can you breed dogs with the same dad but different moms?

Yes, it is possible to breed dogs with the same dad but different moms. However, this is not always a good idea because it can result in genetic defects.

Is it OK to breed dogs with the same father?

Breeding dogs with the same father has the same issue of breeding dogs with the same mother. They will have an inbreeding coefficient of at least 12.5%. 

Each breeder must weigh the benefits and risks of inbreeding, and determine what’s best for their situation. 

What happens if you breed a dog with its father?

Breeding a dog with its father is very close inbreeding. This type of breeding is banned by the Kennel Club, and offspring can only be registered in special circumstances. 

Recessive Genes

Breeding the father and offspring greatly reduces the gene pool. This makes the appearance of recessive genes much more likely. A dog will inherit a set of genes from the father and the mother. 

Recessive genes will only take effect if the offspring inherits the recessive gene from the father and the mother.

In humans, blue eyes are a recessive trait. Brown eyes are a dominant trait. 

People with blue eyes have the gene for blue eyes from their father and mother. If both parents have blue eyes, the child will inherit a blue eyed gene from both parents, and have blue eyes as well. 

If one parent has blue eyes and the other doesn’t, there’s a 25% chance the child will have blue eyes. They will inherit one blue eyed gene. The other gene could be either blue or brown, depending on which gene the other parent passes down. 

Recessive genes are responsible for much more than eye color. Many diseases are caused by recessive genes. 

A large head is a recessive trait in some breeds. Over time, inbreeding made the gene prominent. Today, the large heads mean that mothers must have a c-section, because the head is too large for the birth canal. 

What happens when you breed two dogs from the same parents?

Breeding two dogs from the same parents is never recommended. Their genes will be too similar, which can lead to problems with the offspring. 

Breeding siblings increases the odds of passing on desirable and undesirable traits. Fertility issues, aggression, and behavioral issues become more likely with this close breeding. 

Some breeders state that breeding brothers and sisters provide predictability. It’s easy to know which physical and behavioral characteristics are likely to be passed on. However, it also brings the risk of genetic diseases. 

Siblings From Different Litters

Breeding two dogs with the same parents is brother and sister breeding. It doesn’t matter if they are from different litters. They still have the same genetic material. 

Author

I created and currently manage Pet Dog Owner, the website you can go to when you have questions about your dog's behavior. It is my hope that you find Pet Dog Owner to be a helpful resource. It is also my hope that it will help you to improve your relationship with your dog. You can read more about me and my website here.