Whim Shock
  Working Border Collies and Jacob Sheep  

Border Collie Genetics

I have been vastly interested in coat color and length genetics in Border collies, mainly because as a responsible breeder I should know this stuff and secondly genetics has always interested me. So I did a lot of research and picked many people's brains to learn this. I am always learning and plan on adding to this as I discover new information. I have linked some wonderful sites that include pictures on this subject in the links page. I still need to learn about sables and brindle Border Collies - so if anyone can send information my way on them please feel free to email me:)

Dominant: “One of two words that describe a phenotypic hierarchy among alleles. Given the genotypes, AA, Aa, and aa, there will be two or three possible phenotypes. If there are two phenotypes, that is, if Aa is like AA, the A allele is said to be dominant to the a allele.” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) Will always override recessive.

Recessive: “A recessive allele’s phenotypic expression in the homozygous state is masked in the heterozygous state.” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) One needs two genes for it to show up and can be overridden by a Dominant gene. So can be carried without being seen.

Homozygous: “The state of carrying identical alleles at one or more gene loci.” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) Having two of the same genes either two dominant or two recessive. If the gene is recessive the dog will show that recessive characteristic.

Heterozygous: “The state of carrying different alleles at one or more gene loci.” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) Having two different genes. If the gene is dominant and the dog also carries the recessive only the dominant characteristic will show up in the phenotype.

Phenotype: “Any feature or characteristic of an organism or any group of characteristics. The word phenotype may refer to all of the characteristics of an organism or to one phenotypic trait.” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) I describe this as the physical.

Genotype: “The sum of genes within a cell or within the cells of an organism…” (Woodward, Val, 1992, Human Heredity and Society, West Publishing Company.) I describe this as the genetic or hidden.

Incomplete Dominance: the gene expression is intermediate and does not affect the whole coat, but causes patchy dilution. For example a Merle.

Cryptic: references the problem with the merle sometimes being only a small spot that can be overlooked. The dog is classified as a different color but in reality the merle marking is very small and was overlooked.

Bi: means the dog has only two colors. For example, bi red means the dog is red and white or bi black means the dog is only black and white. There can also be bi blues, bi lilacs, bi red merles, and bi blue merles. We have Tara (bi black), Tucker and Kia (bi reds) in our house.

Tri: the dog has three colors, usually refers to tan markings on cheeks, eyebrows, and under the tail. The Border Collie can have: Black Tri, Red Tri, Tri red merle, Tri blue merle, Tri Blue, and Tri lilac. The tan markings can be so small one can barely notice them or can be very obvious such as our Tri Jake. Shock is a red tri, but he has very light tan markings on his cheeks and under his tail.

So a basic idea of definitions is in place. Now onto the fun stuffJ Border Collies come in a wide range of colors: black, red, blue, lilac, blue merle, red merle, sable, brindle and tri in all of these. Along with coat length can be either smooth (varying lengths), medium/rough (varying lengths). We all know what a black border collie looks like. They are the most common color. The reason being is black is our dominant color. If one breeds a black to a black the puppies will all be black if the parents are homozygous for black. A simple way to remember this is:

Name Dominant/Recessive

Smooth Coat Dominant

Rough/Medium Recessive

Black color Dominant

Red color Recessive

Merle Incomplete Dominant; sometimes referred as "cryptic merle"

No Merle Recessive

No Tri Dominant

Tri Recessive

No Dilute Dominant

Dilute Recessive

ee Red Recessive marking gene - the nose color decides what color it is covering up - a black nose is a black colored dog, a brown nose is a red colored dog.

No ee Dominant

So in order to have a Smooth, Tri, Red Border Collie for example: Smooth is dominant, Tri and red are both recessive so the dog has two genes for recessive for it to be a phenotypic trait and not just a genotypic trait. This dog is homozygous for tri and red, but can be either heterozygous for smooth by carrying medium or homozygous for smooth and would only produce smooth puppies. One wouldn’t know until it was bred to a medium.

Now for a different example: our black female Tara carries red. We found this out by breeding her to Shock our red male. They produced a red puppy. So Tara is heterozygous for Black by carrying red. She is also a medium coat. But Shock is a smooth and carries medium. So all the puppies should be smooth carry medium or recessive medium, the blacks will carry red, and all the puppies will carry tri – since tri is recessive and one needs two genes for it to be expressed. But Tara doesn't carry tri.

Here is the chart for Tara and Shock puppies: t:tri, T:no tri, B:black, r:red, S:smooth coat, m:medium coat

The phenotype of Tara is a bi black medium coat, her genotype is BrmmTT.

The phenotype of Shock is tri red smooth coat, his genotype is Smrrtt.

For the chart: Tara is the first column and Shock is the first line. The puppy predictions are in the middle. Str mtr BmT SmTtBr mmTtBr rmT SmTtrr mmTtrr So technically by the chart I should have seen half the puppies as smooth (carry medium), Black (carry red), no Tri (carry tri) and half the puppies would be Medium (carry medium), Red (Red), no Tri (carry tri). What we actually go was one red puppy (Ace) and the rest were bi blacks, three smooth coats (Annie, Aron & Absolute) and four medium coats (Aiden, Abby, Aya, and Ace).

Now Merle is incomplete dominant. This means the merle coloring can be as small as a spot on the tail, ear, face, or body or as large as a standard merle. The merle can also be referred to as cryptic merle since it can be a small spot and one may not notice it and assumes the dog is not a merle. So if one breeds a merle to a black or red one should see half the puppies come out merle and the other half as what ever Merle is covering up – the recessive gene. Black Merle Black ? Black no merle Black merle Black ? Black no merle Black merle Black ? The question marks are for what the merle is covering up. We would not know because Merle is incomplete dominant. A dilute gene changes the color of the dog from black to blue and red to lilac. It is also recessive so unless the parents are homozygous for it one wouldn’t see the diluted color. The dog could carry and not show and one would see this if the dog was bred to a dilute or another carrier and dilute puppies were produced. This is a basic summarization. I plan to add more as I learn it and I will also work out the Mendal charts for the different crosses. References: Basic Genetics Cryptic (Phantom) Merles Border Colors and Border Collie Coat Colors Coat Color in Border Collies Genetics of Coat Color and Type in Dogs Canine Color Genetics Woodward, Val, Human Heredity and Society, West Publishing Company, 1992