Recently, GEN (Genetic Engineering News) announced that MMI Genomics recectly developed a Canine Heritage test to determine the breed or breeds of dog
in 38 different breeds.
Mainly geared for people with dogs of  unknown breed, it could also be used to determine if another breed was involved with another breed of dog.
MMI Genomics, is a well known and respected life sciences company that utilizes DNA testing  in both animal and humans.
MMI
This company is the most experienced laboratory in the world for canine DNA identification and parentage testing services.
Their accurate and reliable test uses state-of-the-art DNA technology, allowing canine genetic identity to be certified with a confidence of greater than 99.9%.
MMI Genomics is the principal service provider for the American Kennel Club and the United Kennel Club

The test will be available in late February 2007 with the first set of results being produced in mid-March

Tests will cost $65.00 per dog, and will consist of a cheek swab

The 38 breeds will consist of:
 
 

A quote from their article:
.."METAMORPHIX INTRODUCES CANINE HERITAGE™ --
THE FIRST DNA-BASED DIAGNOSTIC TEST TO IDENTIFY CANINE BREEDS
Breakthrough Diagnostic Takes Guess Work out of Establishing Your Dog’s Heritage
Beltsville, Md. January 26, 2007 – MMI Genomics, a wholly-owned subsidiary of MetaMorphix, Inc, announced today the launch of the first commercial, DNA-based, diagnostic test that can genetically determine the breed composition of dogs. Canine Heritage™ is a diagnostic test that uses MetaMorphix’s state-of-the-art, SNP-based, DNA technology to certify up to 38 major breeds. The Canine Heritage™ test is easy to administer and requires only a cheek swab sample to be mailed to the company for analysis. 
Results are returned to owners in 4-6 weeks.
The vast majority of dog owners have no records or information about their pet’s family history. The Canine Heritage™ test can fill that gap. Owners of mixed-breeds, as well as dogs without breed registration papers, can take advantage of this exclusive technology to directly determine pedigree. The identification of parentage is no longer a prerequisite.
MMI Genomics will introduce the Canine Heritage™ test kit at the Global Pet Expo in Orlando, FL from Feb.22nd through Feb. 24th. A list of the 38 identifiable breeds as well as more information on the new product will be available at booth # 2885 and on the company’s website at www.metamorphixinc.com.
“This is very exciting news for dog lovers,” said Dr. Ed Quattlebaum, Co-Chairman and CEO of MetaMorphix, Inc. “The first question always asked of mixed breed dog owners is, ‘What kind of dog is that?’ Now, owners need not guess and can say with certainty,” ‘The Canine Heritage™ test showed that my dog is a mix of Labrador Retriever, English Setter and Border Collie’. In addition to better understanding your pet’s behavior, your dog’s breed analysis can enable 
you to work more closely with your veterinarian to develop a lifetime health and wellness program.”
In the US, alone, rescue organizations and animal shelters account for roughly half of the 6 million dogs taken home per year and only 25% of these pets are purebred. 
Beyond an adopter’s innate curiosity about their new pet, owners are interested in their dogs’ breed composition so they can make informed decisions that ensure happy and healthy lives for their animals.
MMI Genomics has long been a leader in animal DNA identity"

After hearing about this article, and discussing it with others, many felt that this would be THE test that would put to rest once and for all, the merle issue in Cockers.

On Jan 30, a phone call was made to their company and I spoke with someone about this test.

This is what was said , in a nut shell:

1. Yes they DO have a test for Cockers

2. It only goes back and is good for 3-4 generations MAX.

They feel anything back past that is unnecessary. 

I explained to him about the merle issues, 
and he told me that they feel anything past 5-6 generation would be considered PURE BRED, and that going back 8, 9, 10 generations would be "a MOOT point and that the breed club needs to GET OVER IT".
We spoke about the merle being in the cockers from back in the late 80's and all merles traced back to this one dog. He said it sounded to him that this may be a random mutation and that again, after this many generations even if something WAS introduced back then, it was a moot point and these dogs coming down from it would be considered PURE BRED for ANY registry.(AKC, UKC, CKC  etc)
I was told that ASC and some of the other breed clubs who are having a big problem with the merle gene in their breed and can trace it back that far, 
have to again just get over it and stop wasting money on something that is moot.

He said the way they see it, is, if you had a merle something bred to a cocker it would be 50% cocker and 50% merle something. 
Then divide that one 50% merle by 2 for each generation, and you will see that it would NOT be feasible after many generations.
They feel anything with 1/16th of another breed would have no bearing on the normal breed in question.

DO THE MATH:

Merle of another breed bred to a cocker
50% cocker
50% merle
 

50% after 2 generations would be 75% cocker, 25% merle after 3 generations 87.5% cocker, 12.5 % merle after 4 generations 93.75% cocker 6.25% merle after 5 generations 96.875 % cocker 3.125% merle after 6 generations 98.4375% cocker 1.5625% merle after 7 generations 99.21875% cocker  0.78125% merle after 8 generations 99.609375% cocker 0.390625% merle after 9 generations 99.804687% cocker  0.1953125% merle after 10 generations 99.902343% cocker 0.0976562% merle after 11 generations 99.951171% cocker 0.0488281% merle after 12 generations 99.975585% cocker 0.024414% merle and so on.  Many of the merles today are at 12 or more generations down from Rusty Butch

So if Rusty Butch was a  nonmerle (m) who mutated to a merle (M), or Rusty Butch was 1/2 cocker and 1/2 merle something After this many generations
of breeding true, the merle cocker is nearly 100% Purebred.

COMMENTS:
I personally think it is time ASC drops this witch hunt and allow merles to be registered with AKC. The longer they stall, the more confusing and possibly more health problems can crop up because the dogs weren't allowed to be registered the actual color or pattern that they are.
AKC got involved 2 years ago, and told ASC they needed to do something.
If ASC is saying that less than 1 /100th of a percent in a merle cocker isn't purebred, then the club should need to demand that every cocker be tested for impurities from another breed as well. The AKC stud books are not 100% correct; even some show lines have had dogs incorrectly registered over the years. There is always human error, and keeping one pattern out of being accepted by the Parent Club is asnine when the very same thing can be said for other varieties.
Why is it they can accept without reservation, all other cockers even if they aren't bred to standard, but not a merle cocker who DOES fit the standard other than the coat pattern?
What percentage IS a PURE BRED cocker? It can't possibly be 100%, considering the American Cocker came from a variety of DIFFERENT breeds to begin with.
As they say, genes don't disappear, they hide and this is why you can sometimes see a throwback from much earlier times in a litter.
If AKC and genetic experts both deem the merle cocker IS purebred, then ASC may well be setting itself up for a lot of legal issues if they refuse to allow the merle to be registered correctly or accept the merle as a purebred cocker.