A question about inbreeding

Factual Questions
1

A friend of mine has two little kittens she brought back with her from her last trip to her mothers. They make no sound when they meow. When I asked why, the mother told me it’s because of inbreeding; apparently thier parents were siblings, and their parents before them were siblings as well, so it’s become a genetic defect due to that.

We all have heard that breeding within the same bloodline will cause genetic defects to carry on into the bloodline and spread to the offspring. My question is more: how many generations outside of the standard bloodline are required for such genetic deformations to dissapear?

In otherwords, say one of these kittens breeds with a cat that’s not a member of its family? Will their kittens be completely clear, or will there need to be several generations of “no sleeping with your sister” before the defects are finally culled out?

2

You are looking for an expert, not only in genetics, not only in feline genetics, but one with specific knowledge of the trait(s) exhibited by your cat.

I’d suggest having them “fixed” - there are enough curs of every species already.

3

Animals will usually not mate with their siblings by choice because a genetic penalty attaches and the offspring are less likely to survive. I am not sure that DNA destruction through inbreeding CAN be culled out but I am not a geneticist and we have a couple of good ones in here who can speak to that issue.

My comment is to your friend’s mother. “Get the cats fixed if you are going to create a circumstance in which inbreeding must occur for propagation. You are being cruel to the cats and creating baby kittens which are unhealthy, disabled, and whose offspring will likely die. As a mother, how would you like to have babies and see them die one after another or be genetically defective?”

4

In her defense, it wasn’t the mother’s cats, it was her brother in law’s, I believe. The reason these two kittens are in Austin is because my friend couldn’t tolerate the conditions he was letting the cats live in. He didn’t believe in getting his cats neutered, so his general plan of dealing with unwanted kittens was to take them out to the middle of nowhere and abandon them in the while. My friend grabbed four of them and split to give them good homes here in Austin. I believe she’s planning on having them neutered.

5

Your “friend” is an asshole. Men who “don’t believe in neutering” are simply projecting their own sexual insecurity/inadequacy onto whatever animals unfortunate to be their property. They don’t think their genitals are adequate, so they covet and protect those of their pets, and boast of their male dog or cat’s sexual prowess. Litters of pups and kittens are their “proof” of their pet’s (are thereby their own) manliness.
Millions (yes that’s right, millions) of puppies and kittens are born and DIE in shelters each year in this country to unspayed dogs and cats whose owners are too ignorant to do the right thing.

Want a cite: here: http://wa.essortment.com/spayneuterdeba_rbux.htm

Sheesh

6

Inbreeding is bad because it collects recessive traits over and over again, eventually guranteeing that they’ll be expressed in the offspring.

It’s possible that a theoretical genetically perfect family could inbreed for generations with no ill (genetic) effect, but no real life family is so perfect and random mutation will creep in sooner or later.

It’s possible that if the cycle is broken, the next generation won’t show the defective phenotype, but they will be a carrier.

7

I hate to agree with tarpal, but this guy is a fucking lunatic.

I know dozens of folks spending HUNDREDS of selfless hours per year trying to rectify the idiocy of morons like this - Spay and neuter if you love animals. It keeps so many from dying or suffering needlessly. To address the OP, we have a group of chickens that roam the neighborhood. The patriarch rooster is almost certainly (since there are no other roosters around) the father of his OFFSPRING’s progeny, and they’re up to 3 generations now. No 3-legged chicks yet, but I’ll keep you posted.

8

That’s due to inbreeding??? My parents’ cat has a meow like that. Actually, the cat can meow if it really wants to (it’s quite noisy in the car, for example) but its usual meow is almost silent–sometimes a squeak comes out. It sounds like a cat with laryngitis.

The cat was from a shelter, so we have no information about its parents, and it’s also fixed, so we have no information about what its kittens would have been like. I never suspected that particular trait was due to inbreeding, though. It’s been a fairly normal cat for sixteen years.

Aren’t purebred cats and dogs inbred to a certain extent in order to preserve the desired traits of the breed, though? Perhaps a Doper who breeds cats can enlighten us.

9

It sounds like the cats have vocal polyps. Take them to a vet.

10

Good lord, how myths do spread.

FACT: Inbreeding does NOT cause birth defects, unhealthy traits, or “DNA destruction.” Inbreeding permits reinforcement of recessive alleles–that’s it. Inbreeding a healthy and genetically "clean: population does no harm whatsoever (except in an abstract “evlove or die” sense).

FACT: Recessive does NOT mean “bad.” Many fine and useful traits are recessive, and many nasty and deadly traits are dominant. Reinforcing the recessive trait for blue eyes and blond hair in my family only hurts when we forget sunscreen.

I have no idea what cat breeders think of cats that can’t “talk”; I do know that they, and all decent people, think very poorly of those who think it’s better to starve kittens than to neuter or spay their parents.

If you ever meet your friend’s brother-in-law, neuter him!

11

Glad someone finally got to this. All inbreeding does is emphasize existing traits, good as well as bad. Egyptian Pharaohs married their sisters for quite a few generations without noticable difficulty. In case everyone has forgotten, the ancient Egyptian civilization was one of the oldest, longest lasting, and most successful hereabouts.

12

David Simmons wrote: Glad someone finally got to this. All inbreeding does is emphasize existing traits, good as well as bad. Egyptian Pharaohs married their sisters for quite a few generations without noticable difficulty. In case everyone has forgotten, the ancient Egyptian civilization was one of the oldest, longest lasting, and most successful hereabouts.

Uh, wanna back that up, pardner?
The ancient Egyptian practice of incest resulted in some very fucked up people. Lets use the famous Ptolemic line (from whence sprang Cleopatra) which originated in Egypt.

The first couple of generations weren’t too bad. Ptolemy I married several times, once to a distant cousin, Berenike, by whom he had Ptolemy II and Arsinoe II. Ptolemy II married a Thracian princess who bore him all his children. His sister Arsinoe II married first the King of Thrace and secondly to her half-brother, Ptolemy Keraunus. She and Keraunus had no children, and Arsinoe married a third time to her own full-brother, Ptolemy II, but they also had no issue.

Ptolemy III was the son of Ptolemy II and his first wife. He married his first cousin, Princess Berenike of Cyrene, who bore him the dissolute and incompetent Ptolemy IV Philopator, a weak and feeble-minded man who was ruled by his mistress. He married in turn his full sister Arsinoe III. Their son was Ptolemy V Epiphanes, who married the Syrian princess Kleopatra and died at the age of 30. He and Kleopatra produced three children: Ptolemy VI Philometor, Cleopatra II, and Ptolemy VIII Euergetes II.

Ptolemy VI and Cleopatra II wed and had Ptolemy VII Neos and Cleopatra III. Ptolemy VI then died, and his young son (and nephew) was replaced by Ptolemy VIII Euergetes II who married first his sister (Cleopatra II) and then his double-niece (Cleopatra III). Ptolemy VIII Euergetes II was a vicious and savage man, grossly corpulent, very likely psychotic, but also very intelligent. He and Cleopatra II had Ptolemy Memphites, who was murdered by his father-uncle at the age of about thirteen, and then his dismembered body was sent to his mother-aunt as a birthday present.

Ptolemy VIII Euergetes II and his double-niece Cleopatra III had many children: Ptolemy IX Soter II and Ptolemy X Alexander I (like their father/great-uncle, they were both morbidly obese and Ptolemy X Alexander I seems to have been mentally retarded) and Cleopatra IV, Cleopatra Selene, and Tryphaena.

Ptolemy IX Soter II fell in love with his sister Cleopatra IV and married her despite the objections of their mother. She was almost without a doubt the mother of his son, Ptolemy XII. They were forcibly divorced, and he married his other sister, Cleopatra Selene, who became the mother of Berenike III.

Ptolemy X Alexander I married his sister Cleopatra Selene, by whom he had Ptolemy XI. He married secondly to his double-niece, Berenike III, by whom he had Cleopatra V Tryphaena.

Ptolemy XI sold Egypt to Sulla and Rome, returned home, and married his stepmother/cousin/half-sister, Berenike III. He had her murdered, then was torn to pieces himself by an enraged mob. Ptolemy XII was then given the throne, and he wed his cousin/niece, Cleopatra V Tryphaena, by whom he had several children, including the famous Cleopatra VII.

The Ptolemies, especially the later ones, tended to be feeble-minded and grossly fat, and a streak of violent insanity also ran through the family. Ptolemy II executed several of his brothers; Ptolemy Keraunus murdered all but one of Arsinoe II’s children; Cleopatra IV was murdered on the orders of her sister Tryphaena; Cleopatra VII had her sister Arsinoe put to death; Ptolemy XII executed both his wife and their daughter.

Over all, I wouldn’t count the Egyptian pharaohs as being good examples of the benefits of inbreeding.

.:Nichol:.

13

Reading that was like watching a film at 24X speed. By Osiris lost phallus that was fun!

Did you exhale at some point while writing that Nichol?

14

DON’T DO IT, MAN!!

Sorry, that’s my first thought reading the OP title. Carry on.

Oh, about kittens that can’t meow. My cat was that way as a kitten. He would sort of cheep to get attention. Then he watched our other cat, a Siamese who could howl like a banshee, and decided he should meow. So he would take a deep breath, and open his mouth with all his might, and nothing would come out. It was funny to watch. Eventually he learned how.

So maybe they just need to be exposed to cats that meow?

15

Don’t forget that Egyptian royalty commonly drank and ate from lead vessels. Mercury containing compounds were also considered medicinal in that time. Lead and mercury both cause mental detriment up to and including madness, nerve damage, and genetic damage including sperm/eggs. It is a possibility that they slowly poisoned themselves. That would explain why they commonly died at early ages.

16

Well, if the Egyptian Ptolemies were so messed up thanks to mercury poisoning, what was to blame for the deplorable condition of Carlos II von Habsburg, King of Spain?

He was born in 1661, and compared to the Ptolemies, he wasn’t inbred at all; his mother and father were only niece and uncle, after all. Carlos was the only survivor of their brood of five.

Carlos inherited the Habsburg jaw, which on him was so elongated his top teeth did not meet his bottom teeth. He had to be fed by a wet nurse until he was six. Even as an adult, his legs were to weak to support his weight, and he had to be carried everywhere he went. Carlos was mentally handicapped too, and became prematurely senile. He was affilicted with ulcers, dizzyness, what seems to have been epileptic spasms, and diseased bones. He had gone bald, blind and deaf by the age of thirty. Perhaps most alarming to the fate of the dynasty, Carlos suffered from premature enjaculation, and was never able to have any children.

In despair, his first wife, a French princess who was also his cousin, ate voraciously and died young. Someone finally wised up and married Carlos to an unrelated German princess, but despite being exorcized in the hopes of improving her fertility, she never produced any children either. When Carlos died, he willed Spain to the French Bourbons instead of the Austrian Habsburgs, which resulted in the War of the Spanish Succession.

.:Nichol:.

17

No one, except you, said anything at all about “the benefits of inbreeding.”

I don’t really know what I’m supposed to back up. Is it doubted that Egypt was an ancient and highly successful society? Well, in the form we are speaking of it lasted for over 3000 years. That the Pharaohs married relatives is also beyond question, I think.

From the book Man And His Gods, Homer Smith: “It had been the tradition, long before the worship of Osiris became widespread, for the Pharaoh to trace his ancestry direct to Ra, and it was to keep the solar blood uncontaminated that the king usually married his sister, or in some instances his daughter or another divine relation.”

This incestuous marriage custom lasted, according to Smith at least during the Old Kingdom and probably beyond. The Old Kingdom lasted anywhere from 500 (Britannica) to 1000 years (Smith), depending on the source and how the beginning and the end of various eras is figured.

During such a long time there are bound to be a few klinkers among rulers. Such incompetence isn’t unheard of the US Presidents in our slightly over 200 years (in fact I’m thinking of one right now). Can the presence of failures in rulers be entirely ascribed to inbreeding?

18

Recessive traits aren’t always bad, but the worst traits are almost always recessive. Suppose we had some gene which, when expressed, caused a person to die by age five. That’s a pretty bad gene, no? Now suppose that that gene were dominant. Anyone who had the gene would die young, and not bear any offspring. By the next generation, the gene would have completely disappeared. By contrast, if the kill-by-age-five gene were recessive, it might stick around for quite a while, since carriers could still have children and pass it on.

OK, now suppose that a man has some very rare, but bad, recessive gene. Since it’s rare, he probably only has one copy of the gene, and it’s recessive, so one copy leaves him perfectly healthy. Now, he gets married and has children. His wife probably doesn’t have that particular gene at all, although she might have a few (different) rare bad genes of her own. Therefore, half of the man’s children will not even carry his bad gene, and the other half will carry only one copy and not express it, so all of the kids are healthy.

Now let’s suppose that there’s some inbreeding. Specifically, let’s suppose that two of those children then have kids. Each one has a 1 in 2 chance of carrying dad’s bad gene, so there’s a 1 in 4 chance that they’re both carriers. If they’re both carriers, then any given child of theirs has a 1 in 4 chance of getting two copies of Grampa’s bad gene, and therefore expressing it. Even though this disease is extremely rare, then, each grandkid has a 1 in 16 chance of having the disease.

Now, let’s suppose that the original fellow here has 30 bad but rare recessive genes. Very few indeed of the grandchildren will be healthy, now. I don’t know, however, how many “rare but bad” recessive genes a typical person has: This would determine just how likely it is that inbreeding would produce bad results.

19

I think nametag’s point was that inbreeding doesn’t cause birth defects, or character defects, or hereditary diseases. There never was any intent to say or even imply that inbreeding is a good thing, merely that it doesn’t guarantee failure.

One outstanding example of long continued inbreeding is registered thoroughbred horses. They are all from an exceptionally small original gene pool. According to this site the ancestry of all thoroughbred horses can be traced back to fewer than 100 mares and three studs.

Anyway, thoroughbreds have all sorts of problems as a result of recessive genes being expressed; bleeding, high-strung nerves and on and on. One the other hand, the breeding of thoroughbreds also results in some exceptionally fine horses that are well suited for their intended use.

By the way, Charles Darwin married his first cousin and here’s what the Britannica has about that: “Charles and Emma Darwin had 10 children: two died in infancy and a third, Anne, died at age 10. The surviving five sons went away to school. George, Francis, and Horace became distinguished scientists, and Leonard, a major in the royal army, was an engineer and eugenicist. William Erasmus was undistinguished, as were his sisters, who prepared at home to follow their mother into marriage. Henrietta married; Elizabeth remained single at Down.”
That’s not all that bad a record for the middle to late 1800’s.

20

wow, tarpal, way to fight ignorance there. I agree, people should neuter their pets- but sheesh!

El Elvis Rojo, it’s all probability. the first generation of cats might be all clear; they might all be defective. same is true for each successive generation.

but the more non-familial mating going on, the less likely it is that the litters will express the defects.

jb