# brindle bucks



## SarahC

I thought I'd post a picture of a brindle buck.They are always shiny,white and have wavey fur.This is the product of two fawns.Alas he will have to be culled in the next few days to prevent suffering.It's such a shame when he's so wanted


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## WillowDragon

Its such a shame 

He is a beauty, but yes, suffering must be prevented.

Willow xx


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## Alan_Calderwood

hi sarah might be a silly question but i dont under stand why he has to be culled

Alan


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## WillowDragon

It is my understanding that the brindle gene (different from the American brindle) is lethal... bucks usually die before weaning.


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## SarahC

alas they are indeed non viable.


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## Rowangate

what causes them to die?


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## Cait

It's to do with malabsorption of copper.


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## Rowangate

so is it known why it only affects the bucks? Are any bucks viable or do they all suffer. What symptoms would they show?


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## Cait

It's only brindle bucks, non brindle bucks are normal and viable. The brindle bucks die by the age of 2 weeks if left. They wobble and have a low body temperature compared to litter mates as they get older. Here are some pics of one of my previous brindle bucks (culled after the pics to prevent suffering):


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## WillowDragon

Wow... they just look like poor curl astrex mice!! I hope they have obvious symptoms of being poorly =o(

I am hoping to breed astrex in the future, and it would be difficult telling them apart =o/

Willow xx


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## Cait

Brindles are not in the hands of non fanciers as far as anyone knows, and they are unlikely to let any go, certainly not to anyone who wouldn't breed them for show anyway, so you don't have to worry about them being linked to any astrex you get. The gene is dominant too, so the doe has to be a brindle to produce brindle babies.


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## Rowangate

Is this something that could ever be bred out, chin rats use to years ago suffer very badly from megacolon, but over time through selective breeding it has been bred out.


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## Cait

No, I don't think it can be bred out. Variegated mice are also supposed to be prone to megacolon but we see plenty of healthy varies about, for example. I think this is just something the body cannot cope with at all.


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## Rowangate

Understood, thank you for answering.


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## Cait

This might be of interest:
_The Mottle Brindle Mouse Syndrome is a disease in mice which mimics Menkes Syndrome in humans. Treatment of affected male mice has led to varying survival rates in mice and few attempts have led to the development of virile male offsprings in mice and none in humans. In this study the authors examined sperm produced by Brindle mice in an attempt to ascertain reasons for the observed failure of the Brindle mice to reproduce. Microscopic analysis revealed that sperm counts in these mice are higher than sperm counts of the C57/BL or the C57/6J (normal) mice. Microscopically, sperm from Brindle mice showed changes in the acrosomal and flagellum regions. Motility of these sperm were 10% to 50% that of sperm from normal mice. Biochemically, cytochrome oxidase activity was 10% to 50% of the activity seen in normal mice. Hexokinase activity and pyruvate dehydrogenase activity was equal to that observed in normal mice. These observations suggest that infertility in Brindle male mice is due to an impairment of testicular copper transport which leads to a decline in copper dependent processes._

Also:
_The brindled mouse is an accurate model of the fatal human X-linked copper deficiency disorder, Menkes disease. Males carrying the mutant allele of the Menkes gene orthologue Atp7a die in the second week of life._


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## SarahC

They become obviously ill.I don't normally grow them on.Sods law decreed that this litter was entirely made up of brindle bucks and I don't like to leave a mother with nothing.The others have already died,this last must be the strongest.


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## Rowangate

It is such as shame that they have this problem, Brindle's are pretty but obviously not for the novice mouse breeder unless they are fully aware of the problem.


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## SarahC

it is a shame.Then again they have been created in labs for medical science.Without the labs we wouldn't have them at all.That applies to a few mouse varieties.Pearls are another.Mice are the ultimate lab animal.I wonder if it's similar to tortoiseshell cats.They are all female,I know nothing of cat breeding though.I did have some tortoiseshell golden hamsters,again exclusively female.


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## julieszoo

I understand that pearl mice are very rare within the fancy, and at risk of dying out? Do they still exisit in lab populations as well then?


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## Mari

Thank you Sarah and Cait for posting these pics. I've always wondered what the Brindle bucks looked like. So strange that they have the wavy coat! Of course, they're just darling! It really is a shame.  They really are so very different from our American Brindles. I think they're just beautiful! Does anyone have any Brindle doe pics? They are so lovely and I've seen so few pics of them. We don't have them over here. 

Oh, that's such a shame, Sarah, that you didn't get any Brindle does from that litter! It reminds me a bit of breeding harlequin Great Danes. While we don't end up with non-viable males or any sex-linked issues, we always do say that it's 'not for the faint of heart'. When breeding harlequin x harlequin you can very often end up with deaf and/or blind pups. And often, if you are lucky enough to get any show-marked pups in a litter, it's usually the mismarks that have the best conformation!  Seems like a similar breeding endeavor to the Brindle mice! I bet it's sure worth it when you produce a stunning Brindle doe to show, though! 

Very interesting read, as well as the pics!


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## Mari

Also wondering if these bucks live long enough to actually develop any Brindle color, or if they lack any color as a side-effect of the genetic issue, as the wavy coat and pink eyes seem to be? Is this just with a certain color strain (pink eyes, white coat...albino-looking) of Brindles (as they can be any color there, correct?) or with all? Very interesting topic!


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## SarahC

they live to 3 or 4 weeks and remain white.I have just had one born with black eyes ,it's a first for mine.Its still white and shiney,odd.I wonder what causes the satin coat ?along with the colour and the wavey fur it must be a side effect.I thought the danes might be problematic,they are so outstanding and unique to look at that it was bound to be the case.
In answer to the pearl question Julie,I would think it very likely they are held in a lab somewhere or at the very least they have the ability to create them.


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## Oca2

I did a bit of abstract reading today. 

The wavy coat is a side effect of the gene, but I did not find any info about what exactly causes it. Humans with Menkes disease have brittle, kinky and white or steel colored hair, too.

Copper is an essential trace metal, but it is toxic in excess. Therefore copper consentration in the body is regulated tightly. The copper transporter that has mutated in brindled mice is a central wheel in the copper regulation machinery. This broken wheel causes a defect in the uptake of dietary copper from the intestine; this results in copper deficiency in most tissues, particularly in the brain (hence the neurological problems), and copper accumulation in some tissues, e.g. kidney.

Tyrosinase, an essential enzyme in melanin synthesis, contains copper. Tyrosinase is the gene product of the C-locus; complete loss-of-function mutation in Tyrosinase results in the albino mutation (other C-locus alleles result from partial loss-of-function mutations). In both cases the mouse has low/absent Tyrosinase activity and therefore unpigmented coat, but the underlying cause is different. However, in contrast to albinos brindled males do have some Tyrosinase activity; according to Silvers: "The coat of Mo*br males is usually almost white with sooty tips, but sometimes it is light grey in color. The eyes are dark and the ears, tail, and scrotum all display normal levels of pigmentation. -- in brindled males only the skin of the ears, tail, and scrotum is pigmented normally." So I suppose that most SarahC's brindled males have simply been genetically pink-eyed, but there is no reason why they would have to be.

The gene for brindled is located in X-chromosome. This means that heterozygous brindled females (X/X) have another working copy of the gene. Males (X/Y) have only one X-chromosome and therefore only the one dysfunctional copy. Homozygous females show a phenotype that is indistinguishable from brindled males. The brindled phenotype of heterozygous females is because of a phenomenon called X-chromosome inactivation: in females only one of the X-chromosomes in each cell actually works, the other is silenced. The pattern of silencing is mosaic; and nicely visualized in the brindled coat. It follows that since heterozygous females have one working copy of the gene they do not suffer such severe systematic effects that males do (apparently in most tissues it isn't critical for all of the cells to have this spesific enzymatic activity), altough they have been shown to have neurochemical abnormalities (similar, but less severe than males).

Mo*br allele is a spontaneous mutation, so it wasn't created in a lab, though it did arose in a lab population. Many other alleles of this gene do exist, some spontaneous, some created. I should think Silver exists in lab populations, but so it does within the fancy, even if not in UK.

Here is a brief summary of the brindled allele: http://www.informatics.jax.org/javawi2/ ... il&key=197
And Silvers has info about brindled and X-chromosome inactivation: http://www.informatics.jax.org/wksilvers/


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## SarahC

thanks for an interesting read.I'm not scientifically minded so I'll put a question to you if you don't mind.Do you think from what you have read that creating a viable male is a total impossibility?to have a breeding buck would make such an impact.I have heard that some can be grown on but are infertile.We do have silvered mice here,I have silver greys.These have produced light silvered mice with the white undercoat of a pearl but haven't gone the whole hog and become pearls.How to do that is the puzzle .I've looked at the Jackson lab link before but for me I need a dumbed down mouse genetics for idiots type of an explanation :roll:


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## Oca2

SarahC said:


> thanks for an interesting read.I'm not scientifically minded so I'll put a question to you if you don't mind.Do you think from what you have read that creating a viable male is a total impossibility?to have a breeding buck would make such an impact.I have heard that some can be grown on but are infertile.


It is not an impossibility, there have been fertile Mo*br bucks. How do you think the homozygous females were created?  Apparently they are very rare though. I refer you to Silvers.



SarahC said:


> We do have silvered mice here,I have silver greys.These have produced light silverered mice with the white undercoat of a pearl but haven't gone the whole hog and become pearls.How to do that is the puzzle .


Apparently it is a puzzle. I actually know very little about pearls, only what I have read from Silvers and Finnmouse. According to Finnmouse pear is a/a B/b si/si, and Silvers agrees: "in black mice heterozygous for brown the effect of si is greatly intensified; a/a;B/b;si/si animals are lighter than either B/B or b/b silver mice (Dunn and Thigpen, 1930). According to Grüneberg (1952) the whole underfur of a/a;B/b;si/si mice is practically white and "the animals resemble 'reverse agoutis', the hair bases being light, the distal parts of the hairs dark."" Oh, I like that book, even though it is out of date in that today much more is known about the action of many of the genes. :mrgreen:


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## SarahC

well you have been a source of insperation for me.Many thanks.I take it the book is unavailable to you?You will have to trawl ebay


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## Cait

Sarah I have a book by Gruneberg but it is earlier than 1952, you're welcome to have a look but it's pretty heavy going!


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## SarahC

Well I would love a look but you know I rely on you for the technical stuff and for the how to make a .....from scratch.I am going to keep the new blackeyed brindle buck born out of the indestructable reds just incase they pass their indistructable ness on.


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## Cait

For those who wanted pics these are still a work in progress...


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## WillowDragon

That is an amazingly gorgeous mouse 

I am finding this thread fasinating!! The genetics side of breeding, colour and otherwise I am really interested in.

Willow xx


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## Maplewood Stud

cait that mouse is gorgeous  x


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## julieszoo

She is stunning indeed and I can see why people would want to breed them despite the difficulties. This is a very interesting thread


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## Mari

Thanks for the info to those that have posted! The best of luck to those of you working with this difficult, but beautiful strain!

Thanks for the pics, Cait! What a gorgeous girl!

Please keep us updated on your BE buck, Sarah, as well as pics when you get a chance! And anyone else with any developments. This is truly very interesting! I'm loving this thread! I've learned so much.


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## violet1991

i had two white ones in my first litter (wasn't 100% that they were bucks untill they were about a week old).....their mum culled them herself before they opened their eyes. Obviously she knew they weren't right. Though they didn't have wavey coats?

Vi x


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## SarahC

The coat probably didn't grow long enough to show the waves.7 days plus.The pink eyed buck I have at the moment is now at the weaning stage and still going,I haven't checked the black eyed one.I am showing three at the weekend.After the show ,will I be  or  .Time will tell.


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## Mari

The best of luck, Sarah! I hope you're  !


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## SarahC

the black eyed brindle buck perished just after opening his eyes.Simply disappeared without trace.The pink eyed buck is still going strong.Peculiar wobbly gait and tends to suffer from stuck together eyes,apart from that though he seems quite vigorous.The ones that do survive are sterile but I have him in with a group of young does just incase a miracle happens.


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## Mari

Hoping for a miracle for you, as well, Sarah!

The BE buck must have been culled and cannibalized? That's a shame...wonder if he would have made it otherwise, or if he passed away due to his defect and was then cannibalized? Hmmmm.


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## SarahC

just thought I would update this.The pink eyed brindle buck is now adult.Apart from permanently squinty eyes he is quite healthy.I have left him in with a group of brindles plus a self fawn doe.On the 17th of october I introduced a fawn buck to the group( my fawns don't fight) as a back up as I don't want the girls to run to fat and not get any litters.All are heavily pregnant now.I have seperated the self fawn,if she produces a brindle in her litter I will know a miracle has occurred.Of course I expect the fawn buck has done the breeding in which case I'll have a lovely litter of orange babies.


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## julieszoo

Wow Sarah, I have everything crossed for a miracle for you. Would be a lot easier breeding brindles if at least some of the bucks were viable wouldn't it.


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## moustress

That red-eyed brindle is absolutely gorgeous. I've never had to deal with lethal types of yellow or brindle genotypes, thankfully. It's heartbreaking to see babies fading and disappearing after just a week or two. Is that doe mottled or A^y? I'm very intested in knowing about another kind of red-eyed dilute.


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## Cait

moustress said:


> That red-eyed brindle is absolutely gorgeous. I've never had to deal with lethal types of yellow or brindle genotypes, thankfully. It's heartbreaking to see babies fading and disappearing after just a week or two. Is that doe mottled or A^y? I'm very intested in knowing about another kind of red-eyed dilute.


She's neither. She is actually argente, but probably argente with chocolate dilution from memory (the pics were taken quite a while ago now). Just for the record though, lethal yellow babies (Ay/Ay) are never born, they die shortly after conception and then get reabsorbed, resulting in smaller litters. It's different to brindle bucks.


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## moustress

Thanks for the fast answer.


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