Isla

Isla has arrived at her new home in the Poconos.

 And she's made herself right to home! She's a long haired tricolor (black, white, and tan) with a great temperament. She fits the standard to a "T".  

I suppose I should call her color "black and tan with white" but I often list them in the order of their abundance. Does that make sense? They are mostly black so that comes first. White is second most abundant and tan is third.


However, black and tan (together) is the result of a recessive gene called "at". In order to be "black and tan" a dog needs two at-genes. They would be listed as atat. They got one at-gene from mom and one at-gene from dad. Think of a black and tan Doberman or a black and tan Airedale or a black and tan German Shepard. They all have two at-genes (atat).


Three of Isla's sisters are tan, white, and black - again listed in order of the amount of each color shown. The tan shade gene is sometimes listed as Ay. Those three sisters - Saga, Thora, and Sunna - are Ayat. They have a hidden recessive at-gene for black and tan and a dominant Ay gene for tan. Some tan dogs have two Ay-genes. They are AyAy. You cannot tell by simply looking at a tan shade dog whether it has two genes for tan (AyAy) or one gene for tan and another one for black and tan (Ayat). They look identical to the eye.

Virtually all Icelandic Sheepdogs have some white on them. The white is a result of a gene known as the Irish Spotting gene and could be abbreviated as either "I" or "Is". I prefer the latter. Some dogs have less white; others have more white.

I'm guessing that there is a related recessive gene called the i-gene. I'm guessing that a dog with two i-genes (ii) would have no Irish Spotting - no white. I have seen only a few Icelandic Sheepdogs that look like they have no white.








Thank you to Sally.

There is a recessive gene for pied related to the Irish Spotting gene often written as "ip". Remember these symbols only represent a piece of the DNA that produces an identifiable trait in an animal, in our case, our Icelandic Sheepdogs. These genes are usually or most often in pairs.


So dogs with Irish Spotting can be IsIs or Isi or Isip. The first would be a dog with two Is-genes for Irish spotting. The second would be a dog that shows Irish Spotting and has one Is-gene and one recessive hidden i-gene. The third would be a dog that has one Is-gene and shows Irish Spotting but has one hidden recessive ip-gene for pied.)

A true pied dog is ipip; it has two recessive ip-genes for pied and usually comes from two parents who are each Isip. A true pied dog usually receives one recessive ip-gene from dad and one recessive ip-gene from mom.


Some dogs do not have any genes for pied but, nevertheless, show a lot of white. They are often called Extreme Irish Spotting dogs. Although they look similar to pied dogs, usually experienced breeders can tell the difference between Extreme Irish Spotting dogs and true pied dogs.


Before this litter I had never produced dogs with the "Odin Split Faces" and in this litter there were three puppies out of six that showed split faces. 

I was told that split faces probably result from a gene related to Irish Spotting* - perhaps it could be labeled "isf" (sf = split face). If that's true, then each parent must have been "Isisf". That simply put means that each parent had one dominant gene for Irish Spotting (Is) and one recessive gene for split face (isf). The three puppies with split faces - Wodin, Saga and Thora - must have two isf-genes. They must each be isfisf. That's an educated guess.

* However, the split face gene could be totally unrelated to the Irish Spotting gene - I suspect that may be the case. If that is the case, then we would need another symbol to show that. It's possible the gene could be abbreviated simply as sf. Our choices would be either S = not a split face or sf = a split face.
Genes =
S - not a split face
sf - a split face

Dogs
SS - a dog without a split face. It has two genes for normal, non-split-faces
Ssf - a dog identical in appearance to the above - it also does not have a split face. It has one dominant gene for not having a split face and one hidden recessive sf-gene for split face.
sfsf - a split face dog that has two recessive sf-genes for split face.

So just to review. There are four genes that can produce varying amounts of white:
Is = Irish Spotting, a dominant gene
i = its recessive allele (partner) results in no white
ip = pied
isf = split face* see above

Every Icelandic Sheepdog has two of those genes above.

Now a quiz. Describe the physical appearance of the following dogs: - 
IsIs  = 
Isi    =
ii      =
Isip  =
ipip  = 


If you want to go further, you will definitely need a more experienced teacher. This particular one is an amateur and makes mistakes. I know of an experienced canine geneticist in Holland.


Genetics is endlessly fascinating and sometimes quite confusing. Everything that we know about genetics in any plant or animal species comes from actually doing test crosses. As a result of test crosses, geneticists try to come to conclusions about how various traits are inherited.

It will be wonderful to watch Isla and her siblings grow. 

Like her Viking ancestors newly arrived at Iceland from Scandinavia over a thousand years ago, she emerged from her ride, on a plane this time and not a Viking long boat, wagging her tail. That is quite typical for this breed. They LOVE people.