Genetics...

[Susan Stone]

I thought it might be a good idea to start of discussion forum about genetics. Please feel free to add links that may be helpful for members.

I found the following site helpful:http://www.canine-genetics.com/Genetics.htm

and the one Kirsty Williamson found http://www.dogstuff.info/playing_coi_sharp.html


Attached is also the article by J. Gubbels from the Netherlands - thank you Leen for sending it to me.

[Leen]

Secondary epilepsy refers to seizures for which a cause can be determined, and there are many. In dogs less than one year of age, the most commonly-found causes of seizures can be broken down into the following classes: degenerative (storage diseases); developmental (hydrocephalus); toxic (lead, arsenic, organophosphates, chlorinated hydrocarbons, strychnine, tetanus); infectious (distemper, encephalitis, and others); metabolic (such as transient hypoglycemia, enzyme deficiency, liver or kidney failure); nutritional (thiamine, parasitism); and traumatic (acute injury). In dogs 1-3 years of age, a genetic factor is most highly suspected. In dogs 4 years of age and older, seizures are commonly found in the metabolic (hypoglycemia, cardiovascular arrhythmia, hypocalcemia, cirrhosis) and neoplastic (brain tumor) classes. (Oliver, Seizure). Dr. Jean Dodds has mentioned that seizures are also associated with hypothyroidism, which is a familial (inherited) autoimmune disease of purebred dogs.

source http://www.k9web.com/dog-faqs/medical/epilepsy.html

So there is more to it than you could imagine? NEVER underestimate genetics. Some of the underlying causes are genetic.

[Susan Stone]

Henk, I keep having to think about the statement hat "Irish Setters with a COI above 5% over 10 generations are more likely to suffer from idiopathic epilepsy"

To explain, let me say that I asked Leen to calculate Glen's COI over 5 and 10 generations. Prior to this I had thought he was not greatly inbred...
The finding was that his COI over 5 generations was 1.53% - wheras over 10 gen it had risen to 15.38%. Over 10 generations the number of possible ancestors would be 2046 - by comparison Glen has a total of unique ancestors of 408. The record amongst repeat ancestors is held by Wendover Gentleman who appears 94 times.

Having said this, I'd still assume that Glen is probably less inbred than a lot of Irish Setters present today...?
If I assume that the general population of Irish Setters in NL has say a 10 generation COI of 10% (a low estimate!) then how was it possible to find so many non-epileptic dogs with a COI below 5?
How is it possible to demand a COI below 5% over 10 gen when the breed average is so much higher? I assume all the pedigrees of epileptic dogs and non-epileptic dogs were analyzed and the COI calculated to come to this recommendation?

Please don't misunderstand me - you know I also agree we should strive for more genetic diversity. I am simply trying to understand what findings the dutch recommendation is based upon.

And before I get attacked for carrying on about COI and genetic diversity... let me say that I consider this one tool amongst many others for breeding healthy long-living dogs.

[Henk ten Klooster]

Susan,

The website of the club gives no answer on the number of generations used for their statement "the average coi percentage of epileptics is seven". Neither for the number of generations used as a maximum for breeding (=5 now), so this is non-information.

I've e-mailed the coordinator health committee ISCN Jos de Meijer (on this site as well) a few minutes ago asking to confirm the original maximum was 6.25 over ten generations after last years AGM and clarify the number of generations and maximum coi used now plus motivation for first and last.

It is wise to wait for an answer before reacting and hopefully members of the health-committee plus their opposers (both present on this site) will join discussions here.

[Leen]

That’s what exactly is puzzling me too Susan and Henk. On the Dutch site no mention is made of the generations used. COI of a combination not to be higher than 5.0 and average is 7. No mention is made of percentage. Just those 2 numbers.
Also the example given is not correct. Opoe is given as common ancestor. But in both the pedigree and the calculation it is Jacob’s sire and Marie’s dam?
I use 2 pedigree programs PedEx (Australian) and ZOOeasy (Dutch) and the COI calculators FSpeed 2 and PedPower. All 4 give the same results. So I don’t rely on just one program.
COI indeed is just a tool. It does NOT say anything about the health of any given animal in the pedigree. Lower COI does NOT necessarily mean more genetic diversity either.

[Henk ten Klooster]

The number of generations (ten) and maximum percentage for coefficient of inbreeding now (five) for the Irish Setter Club of the Netherlands was confirmed in an e-mail from coordinator health committee ISCN Jos de Meijer.

According to De Meijer, professor Mandigers who adviced the ISCN would prefer a percentage under five. He prefers that personally as well.

'' A low COI has good results on other terrains of genetical defects", writes the coordinator health commitee. "It stops or decreases other genetical defects."

According to De Meijer diving under a 5% coi can be well done in the Red Irish Setter. "You will need to do more homework and maybe travel a bit further", he writes. He states 90% of advices for breeding-combinations in last 1,5 year is under a coi of 5%.

"What is out is grandsire-grandchild combinations or in the line of bitch or dog in first five or six generations the same combination of parents", he writes, adding "And that is good, because there is the source of the biggest misery".

As for low coi and still epilepsy, De Meijer states this happened with one Irish setter.

[Susan Stone]

Yes, Leen I also noted that Opoe was once a bitch, then a dog... not really an ideal example to clarify complicated matters;-))

Thank you very much Henk for getting he correct information. Now we have a clearly defined basis for possible further discussion.

[Astrid Landsaat]

I agree with professor Paul Mandigers as well. Leen calculated Ginger's COI for me over 10 generations and her COI is 12.49%.

What's more important to learn about and ban out epilepsy is DNA research. The plan for research of the ISCN is ready for take off. The only thing that's still missing are blood samples. It's up to breeders and owners to cooperate on this research and I hope we can all work together for a positive outcome.

I think that research is very important for the whole breed. Have you ever owned a dog with epilepsy?

Astrid.

[Belyakova Julia]

Thank you for the links!