154 replies to this topic

[phanilah]

Welcome to the discussion, Lisa - and don't be shy, tell us what you really think. ;)

Beth

[Hadaya]

SCID-Severe Combined Immunodeficiendy DNA Analysis Report
Hadaya Aneek-clear                         report #400015108
Hadaya Sterling Silver-clear              report #400015109

[Heidi]

[Juniper]

Hadaya, on Apr 24 2009, 01:31 PM, said:

SCID-Severe Combined Immunodeficiendy DNA Analysis Report
Hadaya Aneek-clear                         report #400015108
Hadaya Sterling Silver-clear              report #400015109

[diane]

szedlisa, on Apr 14 2009, 08:22 PM, said:

Believe me, breeding horses is not a simple "lets have our pablem served on a silver spoon" affair.
Any desktop breeder who wants to moan is more than welcomed to....I personally prefer the insights of those who have done their research and are willing to share their experiences.

The genetic combination of genes is so immence at the point of the random selecton during conception , that it is no wonder that many breeders have not had either scid or ca foals nor even seen them...no matter how long they have been breeding arabians. Most programs are based on a small number of foundation stock and the careful selection within that group to further improve the bloodlines according to the goals of the breeder. If that seed stock does not carry the defective gene and future outside selections do not either ( or at least have very limited exposure), affected foals are not likely to appear. It has been estimated that there are over 60,000 possible combinations which can be selected to pass forward at *each* conception.  Just how often will one expect to have a defective allele come forward from each parent at the same time?

well written, Lisa.  Hoping that a lot more people read and understand this.

[Melissa]

Matt and I are happy to announce:


SCID DNA Analysis Report
Raja El Halimaar- Clear Result #400015272 Report Date 05/01/09

Melissa

[Heidi]

[LMG]

I've enjoyed these various threads.   It has been quite interesting to see the science begin to make sense of the expression of some of these genetic catastrophes, and as my active science in the lab, is clearly too old, I am finding all the discussion very enlightening.

Since I left the field of investigation at the laboratory level so long ago, and most of my work was either in the legal end of medical matters, or in discrimination on the basis of age, race and sex in the work place, I am, very much looking forward to meeting Pete at the Al Khamsa convention and discussing reductio ad absurdum as a logical device.  "You're female so your proposition sucks," just doesn't cut it anymore.
Tautologies are so old hat.

Lorriee

[Demelza]

Oooh I'd love to be a fly on the wall for this upcoming conversation between Lorriee and Pete.

[Christy Hazel]

Demelza, on May 9 2009, 04:05 PM, said:

Oooh I'd love to be a fly on the wall for this upcoming conversation between Lorriee and Pete.

Me TOO!!!   

I've really enjoyed these posts. Thank you everyone so much for your input. To the owners that have posted their recent results I commend you.!

Christy

[DJ Sheldon]

SCID DNA Analysis Report

Kris Nasama (Shaikh El Sherif x Jai Kris Image)  CLEAR
VetGen report # 400015317

Bint Maalima (Prince Ibn Shaikh x AK Maalima)   CLEAR
VetGen report # 400015318

[diane]

Brenji, on Feb 6 2009, 12:23 AM, said:

When leasing or purchasing a mare , is the seller or the buyer responsible to have these tests done ? Do people test their SE's for CA?
Bren

1. The buyer can request the tests be done and/or view the results or walk away from the potential deal.  It's then upto the parties to agree on who pays if it is at buyer's request.
2. Yes, I've tested for SCID (for clear status on all) and have just purchased CA kits.  This way you know, there's no guessing or what ifs to be concerned about.

[Ray]

diane, on Oct 21 2009, 05:12 AM, said:

1. The buyer can request the tests be done and/or view the results or walk away from the potential deal.  It's then upto the parties to agree on who pays if it is at buyer's request.
2. Yes, I've tested for SCID (for clear status on all) and have just purchased CA kits.  This way you know, there's no guessing or what ifs to be concerned about.

Good on ya, Diane!

[M Huprich]

I sent a note to UC Davis asking about the accuracy of the CA test. I am posting the reply I received from Leah Brault, with her permission to post. I have NOT modified the reply at all:

"You are welcome to pass this information along to others interested in the CA test. Please also be sure to refer them to our webstie on CA (http://www.vgl.ucdav...services/CA.php)."

and also from her in the same email:

"The current CA test is a marker-associated test, which tests for a series of genetic markers in a large area around the known location of the CA gene. Identification of particular forms of these markers that "travel" with CA in the Arabian breed allow us to diagnose a horse as unaffected, carrier, or affected in most cases. In a small number of instances, the test is determined inconclusive. Should this be the case, we report it as such on the results form. This is not a direct test for the mutation that causes CA, as our research in this field is still ongoing. However, as our research moves forward, we find fewer and fewer cases that are unable to be called. The accuracy of the test cannot be determined with certainty, as it is not a direct test for the CA mutation, but our research suggests a high probability of success."

Please carefully read this, including the last sentence.

[phanilah]

I think it is important for people to realize that NO TEST is "perfect" and even though this is a marker based test (which has been reiterated time and time again), that it IS still a useful tool for breeders to use until a direct DNA test is developed.  The preference for testing is obviously a direct DNA test, which tests for the mutation.  But, testing sometimes comes in steps and until the mutation is located (and Davis continues to get closer and closer to locating the mutation) the indirect DNA test provides an option for people to use (or not, as they see fit).

My point is that I really hope people don't read the above (particularly the last sentence) and decide that the test isn't worthwhile or that the results should be ignored.

Beth

[M Huprich]

What is the accuracy of the test? 25%? 50%? 80%? 95%? The UC Davis person that replied said that "the accuracy cannot be determined with certainty". Breeding decisions are being made on the results of the CA test.

[phanilah]

Just for clarification, do you think making breeding decisions with absolutely no guidance at all, is a better option than using a tool that, based on the science to date, is a reasonable option for breeders to use until the exact muatation can be located and a direct DNA developed?

The information published earlier this year in the Journal of Equine Vet Science (from the presentation at the Plant and Animal Genome Conference) outlines how the markers have been developed and the statistical significance of these markers when compared between the affected foal group and the control population.  But, that doesn't equate to an "accuracy %", it simply substantiates the validity of the markers.  

It sounds like you require an absolute number for accuracy, before accepting this test.  I'm sorry that number can't be given to you.  

I can only hope that those who are interested in using this test will understand that not being able to provide an absolute number for accuracy does NOT equate to having an inaccurate test.

Beth

[M Huprich]

It would just be helpful to know how accurate, or inaccurate, this test is.   I think that will determine how useful a tool it is, or how much guidance it's really giving.  Even an accuracy range estimate would be useful.  

I'm sorry but I cannot agree that a test of unknown accuracy is providing reliable guidance.    I have a different opinion in trying to understand the facts of a situation.  I understand that many others have different opinions, too.  

I hope that the reality of its accuracy will be finalized which will make it a useful tool in making breeding decisions.

I would not use a CA carrier test to exclude a stallion or mare, but would then be sure the other horse was also CA tested prior to breeding.  Ditto with SCID.  

Plus all the other problems it would be nice to have tests for - lavender, seizures, schizophrenia, etc etc

And in case anyone wonders, no, I have not lost a foal to SCID, CA, lavender, seizures, etc.  I would like to make intelligent breeding decisions so that I never have to experience this tragedy that others have experienced.

[arabrider57]

Greetings all:

To add my results to the mix (since I dont know where to send/fax them for publication)

SCID results for:

Galaxay Aanuket WZ, Bay Arabian Stallion AHA# 599777.  AK, SE,ASIL

VetGen DNA analysis results:

Report #400015927
Report Date: May 21, 2009
Result:  CLEAR

reviewed and approved by:
Dr George J Brewer

Mark
Windward Farm SC

PS: when the CA result come back I will be happy to post them here as well.
Just got the result on the CA test from Cal Davis and NUKE is N/N. does not possess the markers associated with CA.

[Katrin]

Pete, on Apr 7 2009, 12:18 AM, said:

Beth, can you name one SE horse who is a LFS carrier who was not in the MEN lineage? Just ONE?

Pete took part in a 2005 discussion at theotherforum and should remember. Barbara Lewis named Anter, Abla and their daughter Nagat.