Rat Breeding and Inbreeding

[Xenogenesis]

Just a question that I tried to hijack another thread with yesterday.
Is there any great danger of inbreeding rats?
I was once told that domestic rats are so inbreb they're basically clones so inbreeding doesn't matter?

Cheers
Kyle

[Magpie]

Unless your rats start to get tumors or some other sivkness, there's no problem inbreeding them.

[Xenogenesis]

Cheers Craig

[SlothHead]

Actually, just a strange fact if you will,

THe golden hamster, only found in laboratories now, they are the little rodents that you see in science labs all over the world are all genetically idenitcal to one another.

They all come from the same parent. and are clones of her

[Xenogenesis]

Interesting.

[cyclamen]

i inbreed all my rats, and have never once had a problem, and i have been doing it for a few years now.

[JandC_Reptiles]

I inbreed all mine also.
I wouldn't mind a few offspring with extra limbs, just means more food for my snakes

[SlothHead]

Well Tasmania is still going strong so wheres the problem

[Mayo]

Do we realy want to go there

[herptrader]

I picked up a pair of rats at the last VHS meeting just to introduce some genetic diversity into my (small) colony.

Mamals are a lot more sensitive to inbreeding than species such as reptiles which are genetically more stable having evolved over a much (much much) longer period of time.

[Sdaji]

Originally Posted by herptrader

I picked up a pair of rats at the last VHS meeting just to introduce some genetic diversity into my (small) colony.

Mamals are a lot more sensitive to inbreeding than species such as reptiles which are genetically more stable having evolved over a much (much much) longer period of time.

If you're dealing with highly inbred lines of animals, such as is the case with most lines of domestic rodents, you can actually cause more problems by adding new genetic material than by continuing to breed the inbred lines without it. I'm not sure where the "up to three generations is fine but after that you get problems" type myths which are so common among reptile keepers come from. There isn't some magical number of generations after which inbreeding depression must suddenly kick in; once you get past the point where you've basically eliminated all of the diversity from your line, further inbreeding will have no effect, no matter how many generations the line goes to. If two such lines are crossed (as is the case when two highly inbred lines of domestic rodents are crossed), you're mixing two genotypes which work perfectly well as they were, and the novel genotypes may well have low viability, especially after the F2 (second) and subsequent generations after the cross. Having said that, in all likelihood your rodents will be fine even if you do your best to create poor genotypes, and you're probably crossing rats which originate from the same ultra-inbred line anyway

Perhaps it will be clearer if I put it like this: If you were to go out and grab some wild rats from a genetically diverse population and tried to breed them sibling to sibling for ten generations, you'd probably find that they'd become infertile before you got there, but if you get your highly inbred rats from your local biological supplier, pet shop, rat breeder, etc (which are already inbreed over hundreds of generations), you can breed them sibling to sibling until you're elderly, pass them on to your grandchildren who can do the same until they're elderly, and the rats will be as healthy and viable as the ones you started with.

Someone will probably be wondering "Well then, smarty pants, how did these inbred lines come to be?". That's another story, this post is already too long for most peoples' attention spans

[herptrader]

The issue I was facing was that 3 out of my four tubs (each with 2 females and a male) are hardly producing any babies. I have been running setups in basically the same way for about 5 years giving each trio about a year together and getting good results. Normally Ihave been getting about 150 babies from a trio over their lifespan. In the last year or so a number of my tubs have been producing as few as 40 with long gaps between litters and some very small litter sizes. Interestingly I have always had one tub that has produced at a good rate. I had three females and a male in the grow out tub from these guys and when pair about the same age came up at a VHS auction I decided to do an experiment and now have two fresh tubs. If this does not work I will be talking to Brian about a new set of breeders and starting fresh.

One interesting area of study was the heard of cattle, numbering only a couple of hundred that had remained isolated for centuries and showed no indications of inbreeding.

Actually the whole gentic thing gets more and more interesting at every turn. The lack of genetic diversity in the Woolami Pine really got me thinking.

[Pythoninfinite]

They can slow down from time to time, when this happens to me I just put them all in a big tub and mix the groups, and divide them up again - the new partnerships seem to stimulate them (works with humans, why not rats?) production can increase dramatically if you do this occasionally.

Jamie.

[dee4]

What dangers are you worried about??
They wont mutate in to Ninja Rats or come out with 2 heads or anything
My theory is if they have small litters, use them as feed for your snake. If they have big litters, keep going until they start to drop litter sizes, usually around 18 months old. I have a couple of closely related, some of the females keep getting bigger litters where as others don't have more than 3, these lesser amounts are not a viable option at this house.

[Tatelina]

Originally Posted by Magpie

Unless your rats start to get tumors or some other sivkness, there's no problem inbreeding them.

...that we know of.
If you get down to it..they probably have slight behaivourial issues and what not that we just dont notice.