Lethal guinea pigs discussion

[Alanas]

There is Eye crusties on the left eye but not on the right. I will take her to the vet today. I feel stupid that I didn't just take her in the first place, it wasn't that bad a couple of days ago, it was only last night when I looked at the pictures I saw it was getting worse. Thanks people! I will let you know what he says. I love my vet, he is so cool.

 

[salana]

actually, dal is dominant to all self colours so if you do get a black with one dal parent it is impossible for it to carry the dal gene and have any lethal babies

I just wanted to clear up this misconception. It is possible, not very frequent, but possible for an animal to have one copy of the roan allele (being genetically roan/dal) but have no or very little roaning. This has been known to happen to breeders, who had no idea how their self black sow could be having lethals until they found a couple white hairs under her chin and figured she must be a dal.

The more common way of "hiding" a roan allele is with "bad" markings, usually a lot of white:

You would not know this animal was a dalmatian if she hadn't given birth to a lethal.

Genetically, the roan allele is completely independent of all other coloring genes (e.g. the genes for agouti, black, red, PEW/silver agouti type white, himalayan, white spotting, etc.) not "dominant" over them.

 

[Alanas]

Salana, when people are band do they get sent an email stating in simple language for idiots why they were booted? I see it all the time, Ly & Pigs will say "This is the second time I have warned about chat speak" but they still do it! And like this person on here, was told about this site being anti-breeding etc and she, even after being warned, continued to word vomit her foolish and incorrect information. Are these people really ignorant or stupid or what? What I really can't deal with is that she purposly bred her guinea pigs again knowing that it may result in a lethal pup, not only that, she didn't seem to care that the deaths of her piggies were caused by her own actions, she blames it on her brother wanting a dal, if he really wanted a dal, instead of breeding she should have sent him to the shelter to get one! I am so angry.

 

[fourbwabbys]

Wow, this may be off topic, but we're learning genetics in biology now and I actually get what all of the technical terms are! When alleles, genotypes, recessive and dominant genes are mentioned I don't feel confused. We are starting up a project soon on genetic disorders and I am hoping to research lethals if we are allowed to do it on animals.
Anyway, If breeders aren't familiar with the family's karyotype, they can not know if one or more of the pigs she/he's breeding has the recessive gene and when two recessive genes are presented, then you have the lethal. Most breeders don't realize how in depth they need to know about their pigs history, they just want the profit.

It is possible, not very frequent, but possible for an animal to have one copy of the roan allele (being genetically roan/dal) but have no or very little roaning

That's when they carry the recessive gene and it is not expressed at all because the dominant gene takes over the appearance.

 

[Alanas]

I think it's great that you are going to do your genetics project about piggies, it will keep you interested in the task I think, and maybe you will be a cavy savvy vet one day . I loved genetics at school, I did year 12 biology. I am doing a bachelor of music "4 weeks to go" but I am also doing science outside of uni. I love it. The part I like most is co-dominance. I remember starting out in year 10 with the punet squares giving 4 possible genotypes and pheno types and then by the end of it we were doing 16 and 32 possible results. Love it, Love it, Love it.

 

[Erin8607]

Patrick's mom also has very little roaning, just one spot on her rump of very light blue roan. The other color on her mostly white body was solid patches with no roaning.

She is also satin, so the sheen threw off the roaning to look a bit like glistening hair.

The only heads-up I had for him before his birth was the fact that Opal came in with two other roans, lived with a tri-roan boar (her bother/father of the litter). THe other two babies in the litter were tri-roan, one was dead at birth. Patrick dead at 5 months. Gary and Opal live in the same home and continue to do well. Max, the father, is still in my rescue.

 

[salana]

It gets more complicated, fourbwabbys

The roan allele is partially dominant--it gets expressed if there's one copy, but not completely. It seems like the amount of expression of the roan allele depends on a lot of factors, including the specific problem with the allele, other genes, uterine environment, random chance, and who knows what else.

The way the roan gene works, it controls when and/or how many pigment cells (which are like nerve cells) get sent out from the spinal area of the embryo to spread across the skin. With two normal alleles, everything works well and on time and pigment cells can spread across the entire embryo. With one normal and one broken (roan) allele, the pigment cells leave late and/or in smaller numbers than they should, which doesn't let them cover the entire body. However, how much the cells are affected seems to vary: some roans are nicely roaned all over their bodies, some are mostly white, and some are mostly colored. (The head and butt are normally well-pigmented because they're near the ends of the tube that becomes the spine, and the pigment cells come out of the ends.)

With two roan alleles, the pigment cells never get to leave the tube. That's why lethals have no pigment. Pigmentless ears are very likely to have the nerves die off, causing deafness. The roan alleles seem to screw up the front end of the tube, also interfering with nerve development in the back of the eye, causing blindness. Somehow they affect tooth development too. Different lethals have different problems, although all are white and blind. The different problems are probably because of the same factors as the varying amounts of roaning--other genes, specific problems with particular roan alleles (there may well be more than one, as in all species I know of with problems in this gene, there's at least two deformed variants).

Anyway, that was a long-winded way of explaining the roan gene to you

 

[Cavie Cove]

The roan allele is partially dominant--it gets expressed if there's one copy, but not completely. It seems like the amount of expression of the roan allele depends on a lot of factors, including the specific problem with the allele, other genes, uterine environment, random chance, and who knows what else.

The way the roan gene works, it controls when and/or how many pigment cells (which are like nerve cells) get sent out from the spinal area of the embryo to spread across the skin. With two normal alleles, everything works well and on time and pigment cells can spread across the entire embryo. With one normal and one broken (roan) allele, the pigment cells leave late and/or in smaller numbers than they should, which doesn't let them cover the entire body. However, how much the cells are affected seems to vary: some roans are nicely roaned all over their bodies, some are mostly white, and some are mostly colored. (The head and butt are normally well-pigmented because they're near the ends of the tube that becomes the spine, and the pigment cells come out of the ends.)

With two roan alleles, the pigment cells never get to leave the tube. That's why lethals have no pigment. Pigmentless ears are very likely to have the nerves die off, causing deafness. The roan alleles seem to screw up the front end of the tube, also interfering with nerve development in the back of the eye, causing blindness. Somehow they affect tooth development too. Different lethals have different problems, although all are white and blind. The different problems are probably because of the same factors as the varying amounts of roaning--other genes, specific problems with particular roan alleles (there may well be more than one, as in all species I know of with problems in this gene, there's at least two deformed variants).

Salana is it okay if I copy and past this onto Word so I can print it off? Its a really good piece of writing and I would like to stick it into my Cavy folder.

 

[fourbwabbys]

Thanks salana. This is so interesting to me, especially since it's about something I really enjoy (piggies ) I'm in grade 9 and this is my only honors class and I am doing very well.

The part I like most is co-dominance. I remember starting out in year 10 with the punet squares giving 4 possible genotypes and pheno types and then by the end of it we were doing 16 and 32 possible results. Love it,

That's what we're doing now, I just did very well on a test we had on punnet squares, all types, from 4-32.
I definitely want to go into the animal field, i was thinking about being an exotics vet, but it's hard for me to see animals in pain. Who knows, I may end up being a cay savvy vet one day. Science is definitely my strongest subject, so I want to combine that with animals. I was thinking about going into the ethology field ( i'm pretty sure that's the field that relates to animal behaviour) Animals are definitely a big part of my life and I love doing this type of science to help them.

 

[salana]

Einstein had to be euthanized today. He lost a tooth months ago, and ever since then, he's been on a steady decline in weight, despite handfeeding and supplementation with B vitamins to try and increase his appetite. Today, he was suddenly very cold and lethargic, plus his ears and feet were turning blue. I went to the vet, who diagnosed dehydration and gave him fluids. When I got back home with him, he started seizing, so I had to take him back and have him euthanized.

He was 2 years, 6 months, and 21 days old. I suspect that his eating ability was impaired by losing his tooth, and that he was unable to maintain his weight. The weight loss caused liver problems, and it must have gotten so bad that the crazy liver enzymes made him seize.

 

[CavySpirit]

I'm so sorry Salana. What a great life he had.

Not a good day for our special pigs. My Little Lucy died today, too. My oldest pig and one of my original pigs--pre-rescue.

 

[VoodooJoint]

Oh, T. I'm sorry that you lost Lucy. She could not have had a better, more devoted human though.

 

[Ly&Pigs]

I am so sorry Teresa.

 

[Chloë-Jasmine]

I'm sorry to both of you. I was actaully just telling my boyfriend about Einstien and how good he was doing dispite all his problems. I think I'm going to cry actually. I was holding it in when I read Salana's post and now after reading T's I'm really emotional. I guess we don't realize the connections we make with our online friends and their cavies until something sad happens...

 

[salana]

Another lethal died today too--vince's Cottonball.

 

[daftscotslass]

I am so sorry to hear, Salana. He had a wonderful life and you worked so hard for every moment of it.

 

[The Magic Taco]

I feel really sorry, but I don't know what I can say to make you feel any better.

RIP the world famous lethal, Einstein.

 

[Slap Maxwell]

I am so sorry T and Salana.

 

[Harleigh]

We have a very thourough Medical and Veterinary Library here at Texas A&M University and I am going to look into the gene issue. Most animals have been completely gene sequenced and I have found specific disorders that have been identified on specific genes in the past. I will look into it and see if there has been a more specific test developed to test for true lethals.

 

[salana]

Einstein's histopathology report came back from the lab today. He had almost no lining in his small intestine, so he most likely couldn't absorb almost anything from his food. This would explain why he could eat and eat and eat and still lose weight.