30 replies to this topic

[abcollie]

EOD Status:

The region of the genome where the mutation is located has been conclusively identified (this was reported at the VA finals). The region is 3 million base pairs in the 2500 million base pair canine genome.

The next set of tests they ran typically reveals the exact location of the suspected mutation and with this information they can develop a test.
What actually happened is the next set of experiments was not able to find the exact location of the mutation.

They proposed reasons why they were not able to identify the exact location of the mutation; the most likely is related to the current state of the genetic testing technology and the exact size a location of the mutation. Additional (costly) experiments are being evaluated (in terms of likely success and/or possible benefit to breeders) as a means to aid in locating the mutation; meanwhile, genetic testing technology continues to improve.

Thanks for the info Mark. So, in "layman" terms? It's a mutation but they can't find where it's coming from (and won't be able to until genetic testing improves). So ... does that mean it's like the lottery (the losing kind :@( where it just turns up because something mutates? Both parents have it or they just don't know?

Thanks for keeping up with this ... it's frustrating for people to put so much time/effort/energy into their dogs and have them go deaf just when they are trained.

[backtoblack]

Thanks for the update.

[Sue R]

Thank you, Mark!

[Mark Billadeau]

Candy,

They know the mutation is within the 3 million base pair region and it is recessive (like CEA); where the dog can be clear (2 normal genes), carrier (1 mutated gene 1 normal gene), and affected (2 mutated genes). There may be another gene (or genes) which modifies when the dog goes deaf. These are huge steps forward.

My personal recommendation (unofficially) is until we know more, genetically, we should treat the breeding of EOD lines like we did before there was a DNA test for CEA: don't breed affected dogs, be VERY careful (or don't) cross affected lines (dogs could be carriers), and share information which may help determine which dogs could be carriers.

We will find the gene(s) responsible for EOD, I just don't know when.

Mark



Too bad you're not on this side of the country, we had (all banded now) some REALLY flashy Katahdin ram lambs this year (chocolate & white spotted, tan & white spotted, and a nice set of triplets that were black with white spots).

[Kerales Farm]

Mark, are you saying that it is a simple recessive, rather than a polygenic?

[Mark Billadeau]

Dr Neff believes it is simple recessive in terms of if the dog will go deaf. He believes there may be another gene or genes responsible for when.

[abcollie]

Too bad you're not on this side of the country, we had (all banded now) some REALLY flashy Katahdin ram lambs this year (chocolate & white spotted, tan & white spotted, and a nice set of triplets that were black with white spots).

Thanks!

Would have loved one of your rams ... I beginning to think I live in a "dry county" when it comes to "flashy" sheep :@)

[Journey]

Any new updates?

[Laurae]

This was just published!

http://www.plosgenet...en.1002898.t001

[Mark Billadeau]

There has been no progress towards identifying the exact mutation that causes EOD (which could be turned into a genetic test), only publication of the results to date (see link above). There has been discussions with Mark Neff on several possible "next steps"; some are just in the lab and some involve the working community breeders/owners. Each possible "next step" has difficulties and pit falls which could lead to no progress after expenditures, significant education of breeders/owners, confusion, misuse of information, etc. We have not settled upon the best "next step" which has the least negative impact and the most benefit.

[Journey]

Thanks Mark.