Lethal guinea pigs discussion

I would like some good, clear photo example of Roans and Dalmations as well as some pigs who have been bred which resulted in Lethals, but did not look like Roans or Dals. Also, some really good, clear pics of lethals as well.

Thanks.

Roans:





Also, I'd like a good summary explanation of what dals and roans are and look like in non-breeder and non-genetic terms.

Sorry I don't have any information, but are ALL white guinea pigs lethal? I'm a little bit confused. I have a few white guinea pigs that I've gotten from friends and fostered, but they don't seem to have anything wrong.... except one of them is blind. I think he might be a lethal.

but are ALL white guinea pigs lethal?

Of course not.

except one of them is blind.

What do his teeth look like and how old is he? Do you know what his parents look like?

Sam is about a year old, will be on February 6th. His father is a brown colored crest(sorry, I don't know the fancy names) and then his mother is a self white, or I think that's the name. I don't know about his teeth, I'll go check right now. His mother and father were not inbred, I know that.

T: Could you add something about other deformities on the Lethals reference thread? All of the ones Sharlene had posted (necropsied) had seriously deformed GI tracts. Very abnormal. They didn't have any chance to survive long. Maybe just add other serious defects are possible. I may have missed that mention since I just skimmed over Salana's stuff.

Sure, I'll add that. I think that's why they don't make it anyway, all the internal deformities we can't see.

Yes. Thanks. I wish more people would have pigs necropsied.

Not all lethals die. Some produce perfectly fine, normal offspring. They also make excellent pets. Even the blind ones. Not all whites are lethals. Whites are just one of the many colours cavies can be. They are not albino's per se, genetically. Whites come with either blue, dark, or red (pink) eyes.

Sam has normal teeth, just smaller than my other pigs. He does eat fine and has NEVER had a problem eating his food. I have a question about his weight, though. He is tiny, only 2 pounds and my 3 month old is almost as big as him(he is almost 1 year). Is this something I should be concerned about? He gets enough vit C, is healthy, is he just naturally small? Thanks.

Wow... before coming here, I had no ideas piggies could have lethals, too!

In the horse world, when you breed two Overo paints together, there's about the same % chance that the foal will be a lethal white as with roan guineas. I wonder if it's caused by the same gene? The overo pattern is thought to be caused by something very similar to the roan gene. Usually, when a foal is born white to two overos, it ends up being a lethal.. meaning they pretty much have no digestive tract, often along with a bunch of other problems. In rare cases, the foal doesn't have digestive problems, but is often blind.

I could ramble on for hours (I'm completely fascinated with that way genes work and have been studying the overo paint pattern for years), but I just found the parallels very interesting.

Another interesting note: there's something that can be tested in horses showing any signs of the overo pattern to see if they carry the 'lethal' overo gene... I wonder what the results would be if the same test were done on a roan/dalmation pig that had a lethal in its litter before?

Here's another GL thread on an example of a lethal, with photos: https://www.guinealynx.info/forums/viewtopic.php?p=519169

I have read through lots of books and stuff trying to figure out exactly what my piggies are. I have no idea what a Roan or dal is. I have a great pic of the two of them and I'll take it down and get it scanned in and post it. Maybe everyone can help me figure it out. Of course, they are both boys, so they can't exactly breed (he he) but I would just like to be more aware of what Roans and Dals are. And what mine are!

Tess was a dalmation. She gave birth to a lethal baby who died when he was three days old. She later died from pregnancy toxemia while pregnant with another litter.
She could be a poster child as why breeding pigs is wrong.

https://www.guineapigcages.com/photos/showphoto.php?photo=1613&password=&sort=1&cat=500&page=1

Butthead was the father.
https://img.photobucket.com/albums/v284/tashagurl/ButthadandTess.jpg

In the horse world, when you breed two Overo paints together, there's about the same % chance that the foal will be a lethal white as with roan guineas. I wonder if it's caused by the same gene?

I'm not sure if it's the same gene, but these disorders show up in several animals (horses, humans, hamsters, rats, dogs, cats, ferrets, guinea pigs) and they all involve a particular embryonic development problem, as far as I know. There's not much research on the problem in guinea pigs, but more on other animals. (broken link removed) is a summary of the megacolon problem in rats, for instance.

Basically, nerves develop in a tube down the back of the embryo. Certain chemicals trigger the migration of neurons from the neural tube to the rest of the body. If any of these chemicals are suppressed or delayed, it can result in a delay in neuron migration. The pigment cells migrate too. If they're late, they can't migrate across the entire body and therefore can't pigment all the hair--when an animal has one copy of the allele of whatever gene causes this, enough pigment gets out to create the roan or dalmatian pattern. (Other genes modify how spotty the pig is. Maybe this is why breeders will breed dal x dal, because they can't see the spottiness genes on a self pig.) Typically, the head will have more color and less roaning, and sometimes the rear will be colored as well, as with (broken link removed). This is because the delayed pigment cells can't get as far from the two openings of the neural tube, one at the head and one at the "tail". In Dalmatian dogs, neurons and pigment cells are linked so much that dogs with colored patches on their ears are less likely to be deaf than those with entirely white ears.

In lethals, this entire mechanism is turned off. Obviously some other mechanism can get nerves to some places they need to go, but the absence of pigment cells somehow prevents the normal development of eyes, teeth, and sometimes ears in guinea pigs. In rats, the associated neurons often fail to reach the colon, making it impossible for it to function properly. I don't know if this is related to the digestive problems in pigs--could someone find a detailed report of one or more of these necropsies?

I deleted the previous information I had here about Dalmations since Salana said it was show quality dals that I had posted info on. I don't want to lead anyone wrong, I just wanted to help put a description into layman's terms and I bungled that up. Sorry for the mishap.

That's a show quality dalmatian. Pet store dalmatians are more likely to look like Butthead (above) or (broken link removed), or even be completely white. Suzi has dark eyes, by the way, not red eyes. And the gene can show up in a pig with any kind of hair and any underlying colors--TSW, black, chocolate, red, agouti, PEW, Himalayan, lilac, etc. Any animal that is mostly white could be a "stealth Dalmatian" like Butthead or Suzi. Also, roan is genetically the same thing, and two roans can produce lethals, as can a dal and a roan.

Also, dals have Rnrn, not RnRn. Lethals have RnRn. And many lethals have eyes, they just never work.

Those wacky breeders get so much wrong.

I have a question about roans/dals. Are they just coloured and white? For example all the pictures I have seen have been browns with white or blacks with white. However I have a black guinea pig with brown flecks, sort of like spots but not. I was wondering if that means she is possibly roan/dal?
I'm not sure how to add pictures to a post, I just tried but they said the files were too large.

Thankfully we see very few Dalmations and Roans in our area, though I see there is a localish breeder advertising for some at the moment. A couple of years ago I did take in lovely Dalmation boar, he was soon neutered, so no worries about passsing on faulty genes.

An interesting thread.

My boyfriend took me to a gardening center yesterday because they had pet supplies too. They also kept pets, so off I went to find the guinea pigs. I wasn't too happy with what I found. I saw a roan wandering around. Just as I was explaining to my boyfriend about the lethal gene, another one popped out from under a wooden house. I can only hope they're same sex, but the fact that they had them wasn't really very reassuring.

They also had a poor black self that looked absolutely miserable (it was also missing hair on its head, probably due to a fungus infection.) But I managed to find a store assistant & she took it out of the cage for care. It also had a huge bite mark on its back from fighting. Poor thing.

So, I wasn't really that impressed with that place. The cages were clean with (crappy) food & hay, but I'm not too happy that a place like that is breeding roans. I doubt anyone there really knows anything about guinea pigs genes.

My boyfriend (who doesn't really know about pet stores) said they probably already knew about the sick pig. I doubt it though, because it shouldn't even have been in with other guinea pigs. And when I told him about my concerns of the roans being different sexes he said, "no way! Pet stores keep them seperate, don't they? Otherwise they'd have too many." I'm sure there are many people who thought the same thing & ended up with a litter (& probably lethals too.)