# can you pair brother and sister?



## kerryann (Oct 4, 2010)

not that i have ever done it or even planning to but have always wondered if this can be done?


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## Wight Isle Stud (May 19, 2010)

yes you can. Its called in breeding. It is used to fix good points in an animal, has to be done with care or you will equally fix bad points, unskilled breeders have therfore given it a bad name. Have a play on words, and refer to it as breeding in. Explains it far more acurately.


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## The secret garden (May 13, 2010)

it can be done yes, breeders do it to "fix" trates, ie markings on mice.


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## kerryann (Oct 4, 2010)

ok thankyou very much


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## kerryann (Oct 4, 2010)

i have soooo much to learn.wheres the best place to learn all about breeding. how did all uz guys learn everything u know?i want to learn it all


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## The secret garden (May 13, 2010)

You can't learn it all at once, and if you do your likely to forget it just as quick. It comes with time, patients and you have to want to know. I've been breeding and showing mice successfully for 3 years and i am still learning


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## kerryann (Oct 4, 2010)

i really really want to learn.i know it will take time  wish i could learn it all right now  
how did u first start and where did u learn everything you know today


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## Rhasputin (Feb 21, 2010)

The only bad thing about inbreeding is, if both mice have something wrong (for example, if they were both especially susceptible to cancer) then the offspring will also be likely to have problems, or worse.
You can see this in dog breeds today, as many have traits that cause problems. Dalmatians, for instance, have a coat gene that is linked to deafness.

This is why outcrossing, is sometimes important.


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## Wight Isle Stud (May 19, 2010)

There is a huge amount to learn, no one knows it all, but there is some basic good advice. Do not pair two faults together. (difficult, sometimes you have no choice) Pair the best to the best and success will surely follow. Thats a good starting point for you. Later on when you have more experience you can approach other breeders who will hopefully supply you with a mouse that excells in the points yours lack. Thats the way forward.


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## Wight Isle Stud (May 19, 2010)

kerryann said:


> i have soooo much to learn.wheres the best place to learn all about breeding. how did all uz guys learn everything u know?i want to learn it all


I learnt from my father and the seniors in this fancy, nowadays, my mouse mate and I have about 60 years experience between us. Best place to learn is on here.


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## kerryann (Oct 4, 2010)

i have learned alot since registering with this forum. even though im always asking questions everyone has been so patient and helpful to me


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## Roland (Aug 17, 2009)

Copied from http://drofi.repage7.de/

2009-11-06 Inbreeding, Linebreeding and Crossbreeding
To avoid inbreeding depression it is necessary to avoid close inbreeding. How can we establish a new recessive trait without close inbreeding?

Linebreeding is the way, and paying attention to the inbreeding coefficient is the best way.

The coefficient of kinship is defined as the probability that the alleles at a particular locus chosen at random from two individuals are identical. In the mouse, the coefficient of relationship between parent and offspring is 50%, meaning half of the offspring's genome comes from that parent. Half the genes are identical by descent. The inbreeding coefficient from pairing parents x offspring is 25%. The inbreeding coefficient is roughly half the relationship coefficient.

Linebreeding differs from inbreeding by the pairings which are allowed for.

In linebreeding it is not allowed to breed for inbreeding coefficients higher than 12.5%.

The homozygous offspring showing the recessive trait has to be selected and crossed with other, unrelated partners again. If this procedure is repeated several times, the relationship between the original carrier and the offspring goes below 1% after some circles.

Not allowed for linebreeding:
parent x offspring 25%
full siblings x full siblings 25%

Allowed for linebreeding:
grandparent X grandchild 12.5%
half siblings x half siblings 12.5%
first cousins x first cousins 6.25%
great grandparent x great grandchild 6.25%
second cousins x second cousins 3.125%


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## Jack Garcia (Oct 9, 2009)

Rhasputin said:


> The only bad thing about inbreeding is, if both mice have something wrong (for example, if they were both especially susceptible to cancer) then the offspring will also be likely to have problems, or worse.


That's not a bad thing. It's a good thing because it causes the faults to pop up more quickly and you know to stop or modify that particular line.

All my mice with the exception of one line, are highly inbred. If you want the utmost consistency in type, color, or behavior (whether good or bad), you must inbreed.


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## Roland (Aug 17, 2009)

Jack Garcia said:


> If you want the utmost consistency in type, color, or behavior (whether good or bad), you must inbreed.


No, linebreeding is the way.


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## Jack Garcia (Oct 9, 2009)

Inbreeding is quicker, but harder to do correctly because it leaves less room for mistakes.

Since I am perfect, however, I never make mistakes.

(That last part is making fun of myself! Please don't take it seriously! )


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## Roland (Aug 17, 2009)

Jack Garcia said:


> Since I am perfect, however, I never make mistakes.


Sure, sorry, I forgot!


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## Jack Garcia (Oct 9, 2009)

:lol:


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## Rhasputin (Feb 21, 2010)

Jack Garcia said:


> Rhasputin said:
> 
> 
> > The only bad thing about inbreeding is, if both mice have something wrong (for example, if they were both especially susceptible to cancer) then the offspring will also be likely to have problems, or worse.
> ...


Haha, yeah I guess that can be a good thing.


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## moustress (Sep 25, 2009)

Finnmouse is very good. Simpler yet:

http://www.petrodents.com/index.php

http://www.hiiret.fi/eng/breeding/varieties/index.html

Why isn't their a better sticky on this Forum? With descriptions, pictures, like that? I'm not stepping up to do this, but somebody should. I think it's wierd that a Forum that says 'Breeders' in it's banner has nothing like this. The codes don't really tell one how each color, variety and coat is constituted.


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## WillowDragon (Jan 7, 2009)

My mice are mostly linebred, occasionally inbred.


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## SarahY (Nov 6, 2008)

Rather off topic, moustress, but I'd guess it's because that be a very big thing to put together. There are only a few people on here who could offer good pictures of varieties that look like they should, and the variety selection is very limited between them. Also, Finnmouse is so brilliant that there's really no need for another varieties description website! :lol:

Back on topic, I inbred pretty heavily with no problems 

Sarah xxx


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## WNTMousery (Jun 2, 2010)

I inbreed heavily, as well. I do not have inbreeding depression.

However, I do not pair brother to sister unless I am working with a specific recessive trait. Each pairing should be an improvement on the parents (or at least one parent) and when you breed brother x sister you still get nearly the same thing in the offspring as you did with the parents' breeding which created the brother/sister. I breed father x daughter fairly often, especially when I produce an exceptionally well-typed buck that I want to appear often in my pedigrees.


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## salemouse (Oct 9, 2010)

This is was a really helpful forum for me.  i was under the impression-from ignorance ill admit-that inbreeding was a bad thing. I wont attempt it until i have full knowledge but its good to know.

what is inbreeding depression? also other that faults is there a such thing as a mouse autism and could one get it from inbreeding? ( i know im thinking of people but that all I know, please dont think me unintelegent, im just unknowledgable.


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## Jack Garcia (Oct 9, 2009)

Mice do not have autism in the sense that people do. Our diagnoses include many social and emotional traits that mice cannot display. Dr. Temple Grandin maintains that the natural way animals think is the way that autistic humans think. Her documentary "The Woman Who Thinks Like a Cow" is an excellent exploration into this concept. She is autistic.

Inbreeding depression is a phenomenon which occurs when the gene pool is small AND has harmful alleles present, so that numerous deleterious alleles accumulate in the same individuals and the same population. If you know what you're doing, and guard against breeding from mice with faults, this never happens because you keep animals with faults out of the breeding population in the first place. This is why knowledgeable selection (done by humans) is so important.

There are inbred strains of lab mice who have been bred brother X sister for decades, without suffering inbreeding depression. The opposite to inbreeding depression is heterosis, also called hybrid vigor.


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## WNTMousery (Jun 2, 2010)

To put it very simply, inbreeding "doubles up" or multiplies/magnifies any genes or traits that are already present, whether they be good or bad.


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## Jack Garcia (Oct 9, 2009)

Jenny is right.

Inbreeding does not "create" problems that aren't already there.


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## moustress (Sep 25, 2009)

Inbreeding does not always double up everything, though, there being a hierarchy of precedence, with some genes from one individual and other genes from another individual, so that the result is not always 50/50. That is to say, you may see 53% from one member of a pairing, 47% from the other.


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## WillowDragon (Jan 7, 2009)

salemouse said:


> This is was a really helpful forum for me.  i was under the impression-from ignorance ill admit-that inbreeding was a bad thing. I wont attempt it until i have full knowledge but its good to know.
> 
> what is inbreeding depression? also other that faults is there a such thing as a mouse autism and could one get it from inbreeding? ( i know im thinking of people but that all I know, please dont think me unintelegent, im just unknowledgable.


Autism in humans is not caused by inbreeding either :?


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## Matt Haslam (Mar 13, 2010)

Jack Garcia said:


> Mice do not have autism in the sense that people do. Our diagnoses include many social and emotional traits that mice cannot display. Dr. Temple Grandin maintains that the natural way animals think is the way that autistic humans think. Her documentary "The Woman Who Thinks Like a Cow" is an excellent exploration into this concept. She is autistic.


Love that docu Jack, there is an excellent Film also entitled 'Temple Grandin' . great film amazing woman.


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## Jack Garcia (Oct 9, 2009)

After showing him the documentary, one of my friends called me "The Man Who Thinks Like a Mouse." :lol:


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## Roland (Aug 17, 2009)

Hi,

I think we should have a more differentiated look on this important theme. Therefore I have opened another thread. I hope you will enjoy it and get some benefit from my thoughts:
viewtopic.php?f=26&t=5144

All the best, Roland


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