Why does inbreeding cause deformed puppies?

Answer 1

Fairly simple really:

If say you had a condition like arthritis in your family line, then by marrying in, you stand twice the chance of inheriting it, twice the chance of a much more severe form of it!

If you have mental health problems, twice the chance of much more serious mental health problems being passed on inside your line.

New blood, non related, dilutes this chance of deformity, thus, making the line stronger!

Answer 2

Inbreeding does not automatically cause deformities or defects.

What happens is that the closer or more often you inbreed, the more likely the parents are to carry the same genes. If the genes are good ones, then you get really good dogs. But if the parents each have a recessive gene for a problem, then it is likely that some of the puppies will have that problem, and most of the rest will be carriers.

This is why it is very important to have a good knowlege of genetics, the inheritance modes of genetic diseases and the dogs involved and their families before attempting inbreeding. And you must be willing to cull anything that is defective.

Done properly, inbreeding can actually be used to eliminate genetic diseases. There are now strains of disease-free laboratory mice which have been carefully inbred for many generations and selected for health and vigor.

Control of Canine Genetic Diseases by George Padgett is an excellent book on the subject.

Answer 3

The biggest risk with inbreeding is the fact that both are likely to carry the same genes, particularly recessives. Recessive genes can be carried by the parents, but not expressed meaning the parents don't have the disease, but carry it. In order for them to be passed on, both parents have to carry them. Since inbreeding lines are related, there is a much higher likelyhood that they will both carry these genes, meaning there is a much higher likelyhood the offspring will inherit them. Recessives can be both good and bad, obviously we are concerned about the bad ones. Many diseases are also genetic. Again, since both parents share the same genetics, there is a much higher likelyhood the offspring will inherit them. Close inbreeding is never a good idea unless the breeder has extensive knowledge in genetics (think PhD) and their lines, but it is not always disasterous. The puppies may turn out to be fine, however, it is never worth the risk to do it intentionally. Dogs were created out of selective breeding of wolves. Their was a wide gene pool available that we humans selectively bred down. They didn't just come from two dogs. Unless there is a disease relating to it or the parents have severe temperament faults, there is no reason an inbred dog should be any more likely to turn on its owner.

Answer 4

Lack of genetic diversity.

When you are faced with a small population, any population such as a secluded herd of sheep on one small mountain peak, they eventually run out of different partners to pair up with. So eventually you have brothers and cousins interbreeding. It is actually natural in small populations especially ones that are endangered.

However when it comes to dogs people breed them for certain traits and temperments and forget about the generations and relationships among their breeders. So they end-up inbreeding. They think it will produce better puppies with cuters faces, better stances, or longer noses.

When this happens you are limiting the gene pool or limiting the genetic diversity amoung your population. So instead of the perfect puppy you end up with genetic deformities or anomolies popping up in the DNA.

This does happen naturally, and explains why there are genetic disorders in humans, it is not always inbreeding, however when certain pieces of genetic code contact each other in certain conditions they can cause these spontaneous changes, that helps explain evolution. Since all dogs are one species and different breeds are just subspecies or hybrids that evolved from people breeding one dog with one that looks different from the first one.

This also explains how you get your father's eyes and your mother's nose.

Sometimes in the pursuit of perfection, we create mutations that we cannot remedy. Some call it playing GOD, I call it evolution. It is natural but since the pet trade is governed mostly by profit, people look to make the next one bigger, faster, smarter, calmer, cuter....it never ends.

It is all about genetics. The more diversity you have, the stronger your population. The less diversity, the weaker your population.... look at the royal families of ancient Europe, inbreeding was done to keep the blood line pure, and it ended up creating hemophilia, and children who rarely made it passed infancy... it weakened the population and not many decendents reamain.

Answer 5

Simply put, too close a relationship between any animal (not just dogs) means the parental genes are repeated causing defects. This is why we are not allowed by law to marry close relatives. Even cousins allowed to marry increase the risk of having children with deformities or diseases.

Answer 6

i dont know much about dogs, but a little about genetics. This happens for the same reason that when human cousins mate, there can be defects (comon in Pakistan for example)

Im no expert, but ill try make it simple. We all have 2 genes for all our charectiristics, for example you may have blue eyes, but you will have blue and brown eye genes, but the blue were the more dominant - so you have blue eyes. That Brown gene will always be there in the background. Same applys to defects, we may have a defected gene, BUT the good gene won the battle, so the defect is hidden.

If you sleep with your cousin who has the same dodgy gene in the background thatn its likely the power of the 2 combining causes the defect to be exposed.

Im only GCSE level, so someone may explain it better - but a level is prob 2 complex anyway.

Really hope that was clear

Answer 7

Inbreeding is also common in the Manchester area. Visit the shopping precinct in Salford and you will see an example of what i mean. Massive foreheads and slow shuffling crooked feet all round and so many people on crutches and in wheelchairs but i think thats more a case of benefit fraud! lol

Answer 8

Its all in the genes. One of the reasons mutts seem to be more resistant to disease is their gene pools are far related. That is why pure breds are registered (1 of the reasons anyway) When a gene pool is too closely related it increased the possibly of a defect out numbering the good genes (just to put it simply).

Answer 9

It does happen for all of the reasons stated but not as commonly as you might think. It is not uncommon for breeders to mate very closely related animals in an attempt to "lock in" desirable characteristics within a line. We have selectively mated all-sorts of domestic animals to obtain desirable characteristics for centuries.

Answer 10

It's just like a person, when their genes are crossed, there may be some that are the same, which causes the defect in the pup.