I have to admit that geek that I am, I love genetics (it was about my favourite class in university) and therefore, I'm going to make this post about coat colours. Coat colours in dogs are usually very complicated because there are many genes involved--from genes that control the colour to genes that control the markings to modifier genes that change the amount of pigment. If you were too lazy to read the two links that I shared in the last post, here's just a quick summary of the colours that Papillons and Cavaliers come in.
They share these colours with many other breeds of dogs, but sometimes they are called different names in other breeds. Let's start off with Cavaliers because they only come in 4 colours and are governed by simple genetics.
Cavaliers come in 2 varieties--particolours and wholecolours. "Particolour" is the dog term for coats that have patches of colour on white fur. The particolouring is the result of the piebald gene in dogs. Particolours are recessive to solid colours, as outlined here. The most common colour that Cavaliers come in is Blenheim (red & white). Lyra is a Blenheim Cavalier, clearly... but for the sake of this entry.. here's a picture of her:
The other particolour variety of Cavalier is the tricolour Cavalier. They have tan (brown colour) spots above their eyes, cheeks, and base of the tails. Tricolour is the hardest colour to breed for in Cavaliers because the breed standard calls for a blaze (the white in between their eyes) and a broken up coat (patches of white). Unlike Papillons who are predominantly white (a result of the extreme piebald gene), Cavaliers have much more colour on their coats. In tricolours, the piebald gene is not expressed as strongly as it is in Blenheims, hence tricolours tend to turn out too solidly black for show or breeding. Here's what tricolours look like:
Next, we have the whole colours. The first type of wholecolour is basically a dog that's solid red--in Cavaliers, this colour is called "ruby". If you looked at the link I shared above, you'll see that Rubies are basically Blenheims without the piebald gene or with only 1 copy of the piebald gene (remember, piebald is recessive, and coat colour inheritance in Cavaliers follows the simple Mendelian dominant-recessive pattern). Here's a ruby coloured dog:
The last colour that Cavaliers come in is Black & Tan. They are basically tricolour dogs without the piebald gene expressed, so they have no white patches on their bodies. Here's what they look like:
Cavalier breeders usually focus on either particolours or wholecolours only, because breeding a particolour dog to a wholecolour dog risks the production of wholecolour dogs with mismarks--these are ruby or black & tan dogs who have white markings on their bodies, such as this dog:
See how it has a thin blaze and white on its muzzle and neck? These are faults according to the breed standard. Of course, they are perfectly healthy and make great pets, but breeding successive generations of wholecolours to particolours will increase the incidence of mismarks.
Cavaliers used to come in other colours such as sable (red mixed with black and white), chocolate and black (solid black), but these were written out of the breed standards decades ago so you'll be hard pressed to come across them today. These colours still exist in other spaniel breeds such as Papillons, Cocker Spaniels, and Kooikerhondjes.
Since this post has gotten so long, I think I'll write about Papillon coat colours in a separate post. Papillons come in a lot more colours and because they do come in sable, it'll be a long post! The sable gene does not follow a simple dominance inheritance, so the amount of sabling varies in each dog. Modifier genes such as dilution also occur in the breed, so stay tuned for part 2.. it'll be even longer than this one!
Blog for the Dogs
Here's where I chronicle the dogs' daily lives, write reviews on dog products, and share tips on everything under the sun.