inbreeding

[nixer]

inbreeding with mice is considered when it has been mated brother x sister for 20 or more consecutive generations (F20). All offspring can be traced back to a single ancestral breeding pair in the 20th or subsequent generation. Such inbred strains are 98% identical

[Hyper Joe]

It would take a while before the inbreeding shows bad results.
This would be just one way to do it without getting new stock.
This should last for a few years or more.

1 - Breed founding father to founding mothers for about 8 months or so.
You get 8 generations of babies not bred back to the parents yet.

2 - On the 8th month breed the father to the newest daughters.
-Inbreed level 1- and it has already been 8 months!

3 - Keep a male from the 8th month and breed him to the daughters from step 2 or their daughters.
Or keep a male from the original fathers breeding to the 8th month daughters and breed back to them.
- inbreeding level 2 - then another eight months go by.....
Or keep a male from each female litter and breed to daughters from the other females litters.

Hehee.. I think I made this sound too complicated but.. the easiest way to keep your bloodline fresh just get a new male every 8 months and breed to the newest daughters.

[nixer]

It would take a while before the inbreeding shows bad results.
This would be just one way to do it without getting new stock.
This should last for a few years or more.

1 - Breed founding father to founding mothers for about 8 months or so.
You get 8 generations of babies not bred back to the parents yet.

2 - On the 8th month breed the father to the newest daughters.
-Inbreed level 1- and it has already been 8 months!

3 - Keep a male from the 8th month and breed him to the daughters from step 2 or their daughters.
Or keep a male from the original fathers breeding to the 8th month daughters and breed back to them.
- inbreeding level 2 - then another eight months go by.....
Or keep a male from each female litter and breed to daughters from the other females litters.

Hehee.. I think I made this sound too complicated but.. the easiest way to keep your bloodline fresh just get a new male every 8 months and breed to the newest daughters.

the only problem with that is its not inbreeding. none of those mice would carry all the same genes. what i posted is what harlan teklan deems inbred

[MarkS]

I haven't added new stock to my current colony in the three or four years that it's been going and I won't either. I've spoken to several rodent breeders who have told me that they've had their colony crash after bringing in new stock.

Any time you bring in new mice, you also risk bringing in the diseases that they may have. I don't know how many generations I've gone through, I don't keep my breeders around for very long, maybe 3-4 months at the most so I'm sure they're fairly well inbred but I haven't noticed any harmful effects. I'd much rather risk a little inbreeding depression then lose the whole colony by bringing in new stock with diseases that my colony may no longer have any immunity against.

[kc261]

Any time you bring in new mice, you also risk bringing in the diseases that they may have....(stuff deleted)....I'd much rather risk a little inbreeding depression then lose the whole colony by bringing in new stock with diseases that my colony may no longer have any immunity against.

That's a good point, and I had not thought of it that way. If I were to bring in new stock, I would obviously quarantine. However, that doesn't necessarily protect against something the new stock is carrying but does not show symptoms.

I think another thing is a lot of people misunderstand inbreeding. It does not cause bad genes to spontaneously appear. Random mutations do occur, but that will happen whether or not your are inbreeding. What inbreeding does is increase the chances of a bad gene becoming widespread throughout your colony. If you have a colony that has good genetics, or even if you have some bad genes but have enough good ones and selectively breed for the best animals, you should be able to maintain healthy stock even if it is extremely inbred.

Please note I am speaking hypothetically and based on what I have read & heard from people who do have the experience of inbreeding their mice for many generations. Although I have already done some inbreeding in my mouse colony, I just haven't been at it long enough to be able to speak from experience as far as long term effects.

[nixer]

if you have any bad gene in your collection with inbreeding it will bring it out eventually it doesnt matter if only one mouse carried the gene or 5. i have seen ppl get it usually it results in deformed babies or offspring that seem fine but usually around weanling time they will start to run in circles stuff like that, but also if you get lab mice they could also carry something more serious such as cancer or any of the other genetic diseases

[Hyper Joe]

the only problem with that is its not inbreeding. none of those mice would carry all the same genes. what i posted is what harlan teklan deems inbred

That is Harlan Teklan. That is their terminology not necessarily the correct one.

Definition:
Inbreeding is breeding between close relatives, whether plant or animal.

Another note: Linebreeding is a form of inbreeding.

There are various websites that have definitions for inbreeding, line-breeding, outcrossing and outbreeding.
Here is just a few.

http://www.bulldoginformation.com/breeding-types.html
http://bowlingsite.mcf.com/genetics/inbreeding.html
http://www.netpets.org/cats/reference/info/inbreed.html
http://members.tripod.com/~Marge_S_2...inbreeding.htm

This one is very interesting.
http://goto.glocalnet.net/rat/gen/inbreeding.htm

[M&J in NC]

I bought them all from petco (only place i could find that sold mice live) so i am sure they are all related.

Here's what we did... There is only one pet store in our town, and the owner breeds his own mice. We bought 6 females from him. Then we drove 45 minutes to the nearest Petco and bought 2 males. Then we made two 1.3 colonies. All 5 females are bred (1 died) and the 2 males have since been fed off. When the babies reach 2-months-old I will separate the entire colony into male and female groups. Then they will ALL be fed off. Next year I'll repeat this process. There may be an easier way, but I am 100% sure that my mice are not inbred, and I think that makes for healthier mice. JMO

~ Michael

[Brandon Osborne]

if you have any bad gene in your collection with inbreeding it will bring it out eventually it doesnt matter if only one mouse carried the gene or 5. i have seen ppl get it usually it results in deformed babies or offspring that seem fine but usually around weanling time they will start to run in circles stuff like that, but also if you get lab mice they could also carry something more serious such as cancer or any of the other genetic diseases

Running in circles is cause by an inner ear infection. It creates an unbalance in the equilibrium and is even more noticable when they are picked up. It has nothing to do with inbreeding. I'm not sure if it's caused by bacteria or just a weakened immune system.

[Brandon Osborne]

There may be an easier way, but I am 100% sure that my mice are not inbred, and I think that makes for healthier mice. JMO

~ Michael

Not necessarily. Some strains of inbred mice are actually very hardy and produce very large litters. Harlan has strains that produced average litters of 14-16 and adults retire at around 60 grams. Sometimes outbreeding will weaken the genes as mentioned above, as well as the immune system.