We just adopted a two year old rat terrier from a shelter and had some questions.  so far Herbie has been great, no accidents inside and he is just as happy playing hard or napping in his bed.  He does love to burrow under the covers of the bed and would rather have treats than eat his supper.  He came with some papers and it looks like he came from a kennel in AR, Run-N-Ridge (we're in Oregon).  He is black/tan merle (his photo is in the avatar) .  From what I've been able to find on the net merle is not desirable and may be associated with some health defects?  Does anybody know what the health defects might be?  I'm not interested in showing Herbie but I would like to know if there is anything I need to look out for health wise.  Thanks for your help.   

I just did a quick Google check on merle.  If I'm understanding it all correctly the danger in merles is in breeding 1 merle to another merle - the puppies then run the risk of having sensory organ problems - hearing or sight problems.  Breeders who are responsible and want to produce merle do it with mating a merle to a non-merle.  Your pup is probably fine but by contacting the breeders they can explain their program to you.

From Wikopedia:

"Merle is actually a heterozygote of an incomplete dominance gene. If two such dogs are mated, on the average one quarter of the puppies will be double merles ("double dilute" and some percentage of these double merle puppies could have eye defects and/or could be deaf. Knowledgeable breeders who want to produce merle puppies mate a merle with a nonmerle dog; roughly half the puppies will be merles without the risk of vision or hearing defects.^ΐ]"

^{And from http://www.artaukc.org/pg4.htm:}

Merle
Is called Dapple in Dachshunds. The Harlequin Great Dane is genetically merle. Merle is associated with health risks involving the sensory organs, i.e., sight and hearing. When merle is bred to merle the risks escalate and may even result in death to the fetus. Dog breeds that allow merle and breed for this pattern must handle those risks with great care.

And from the Rat Terrier Club of America site (they are the ones trying to get ratties recognized by the AKC (other than foundation stock): 

DISQUALIFICATIONS

Short-legs, and/or benched legs or fiddle front. Absence of coat, wirehaired, broken-coated, or long coated or longhaired individuals. Absence of minimal patch of white the size of a quarter (approximately 1 square inch) displayed on body, excluding the areas of the head and feet. Single or solid colors; Solid white, or near solid white (excessively white patterned) dogs, not displaying mottled skin and dark nose leather. Albinism, or brindle or merle colorations. Dogs not measuring 10" inches of height at 12 months of age, or those measuring over 19" inches. Wry, undershot or overshot bites. Blue, China or Walleyes, disqualified. Monorchids or Cryptorchids. Cropped ears.

Herbie is a doll! Love his name too.

Hello,

I am the Running Ridge owner in question that is being discussed and I am greatly disappointed that one of my babies was placed in a shelter/rescue.  My contract clearly states that ANY puppy/dog sold by me is to be returned to me if the purchaser can no longer keep it and NOT placed in a shelter, Sold or Euthanized for any reason.

The previous owner illegally and without contacting me has violated the contract and I will have to look into my options.

For as the merle gene goes there are NO ill health concerns when breeding Merle in the single form. 

Guess I'm a little disappointed that you felt the need to go on the internet to make assumptions when I'm quite easy to find by a simple SEARCH. 

Welcome to you and Herbie!!!