Early research shows a genetic component to KS

[SO1]

There does seem to be a lot of KS around, possibly because of better awareness and vets suggesting it for poor performance works up more often than perhaps was the case 20 years ago, or possibly if it is genetic and there are some popular breeding lines that carry the gene then it could be turning up more often in the equine population.

If it is found more commonly in horses compared to ponies and more in certain breeds it won't just be because of the way the horses are ridden.

If there is an easy inexpensive genetic test that shows up susceptibility then I would not surprised if people started asking for this as part of pre-purchase examinations.

 

[shortstuff99]

Yes genetics can get very complicated and it is not just as easy as dominant and recessive. You can start getting into things like recombination, mosaics, modifying genes etc and then there is phenotypic expressions being altered by the environment, random mutations et al.

Probably best to not breed from horses with known problems, but they will need to know the full function of the genes and other things that determine kissing spines before saying what must be tested for.

 

[Marigold4]

My understanding is that HWSD is caused by a single mutation, and it is completely recessive- i.e. there is no way that a carrier can display symptoms of the disease. In this case, there are less negatives to breeding from a carrier with an N/N mare. It's also relevant that there is an easy and cheap test for HWSD and the Connemara pony society requires carriers to have this recorded in their passport.

Personally, I think there are enough quality connemara ponies out there that are N/N- so there is no need to breed from a carrier. If this was done, you could probably remove the HWSD gene from the population entirely, which would benefit future generations. If we were talking about a much smaller population, I might feel differently!

The genetics of KS seem a lot more complex, and it doesn't seem like we fully understand how the three genes interact, how the genes interact with the environment or if other genes might be involved too. Due to this, I don't think it would be ethical to breed from a horse which showed symptoms of kissing spine, even if the other parent was healthy.

If, with future research, it was found that the mutation on Chromosome 14 was a true recessive gene regardless of environmental factors, (for example) then there might be reasons to breed from a parent with the mutation and produce offspring which are carriers. But the Chromosome 16 and Chromosome 25 genes seem like they could impact animals that had KS with purely environmental causes (and the research so far suggests that there may be some cases which are purely environmental).

I hope that makes sense!

Thanks and yes, your explanation is lovely and clear. Genetics are fascinating! I am determined to find out more!

 

[Gloi]

Thanks and yes, your explanation is lovely and clear. Genetics are fascinating! I am determined to find out more!

I still had Fell ponies when the Fell pony syndrome came to light and my friend lost a foal to it. Nobody knew what it was at the time and it was very worrying. Now they have a genetic test they can avoid breeding two carriers together but because of the small gene pool have not avoided breeding from carriers altogether.

https://www.animalgenetics.eu/Equine/Genetic_Disease/FIS.asp

 

[Gloi]

Before genetic testing with the Fells it was possible for less scrupulous breeders to hide that they had the problem in their stock. Now the status of breeding stock can easily be determined this is less easy. The same with Connemaras. I hope future research will help with reducing all the other genetic problems ?