Once explained by educated guesses based on folklore and assumptions, we can now predict colour in our Highlands based on science with a fair degree of certainty.
At the end of this discussion there are some charts to help you work out what colour calves you can expect with certain matings.
The reason we can do all this is that DNA tests can now be performed to evaluate the actual colour of Highlands, as determined by what genes are at the three of the six loci that control colour in Highland cattle.
At each of these loci, every animal has two genes – one from its dam and one from its sire. That we are aware of at the moment, the loci & gene options are as follows:
|Locus||Function||Known genes at this locus (*)|
|E||determines black vs red||ED, E+, e|
|D||dilutes black and red colours||DH, +|
|A||brindle pattern (when E+/e or E+/E+)||Abr, A|
(*) written with more dominant gene first. The second gene in each case being the “wild type” gene, or default colour of what is thought to be all Brittish breed cattle, and possibly the Auroch.
Genetic make-up of each of the seven known colours:
|Coat Colour||E locus||D locus||A locus|
|Black||ED||any||+||+||Abr or A||Abr or A|
|Dun||ED||any||DH||+||Abr or A||Abr or A|
|Silver Dun||ED||any||DH||DH||Abr or A||Abr or A|
|Red||e or E+||e or E+||+||+||A||A|
|Yellow||e or E+||e or E+||DH||+||A||A|
|White||e or E+||e or E+||DH||DH||A||A|
|Brindle||E+||e or E+||+||+||Abr||Abr or A|
This has been known about for some years and accounts for the 2 basic colours – red and black. Black (ED) is dominant as in black Angus. This means that for an animal to be black, it must have one (or possibly two) of these ED genes. For a calf to be black (or dun or silver dun), one of it's parents must have given it the black ED gene, and so must have been black (or dun or silver dun) themselves.
Therefore a black (or dun or silver dun) animal can not come from two red parents (or yellow or white). The only way this could happen is if there was another gene for black somewhere that was recessive – and this may be possible but hasn't been detected in DNA tests so far. There appears to be a higher prevalence of black offspring from brindle parents. If anyone has any of these such black calves born, I would love to follow them up. I have only had the opportunity to follow one of these up thus far, and sadly discovered that the suggested sire was not the sire (on DNA parentage verification tests) – someone jumped the fence!
Red animals can be red (e/e) or 'wild type' (E+/E+, or E+/e) but they all look the same. In some 'wild type' animals (only bulls that we are aware of), there will be some quite obvious black hairs stippled around the face and down the neck and legs. The 'wild type' (E+) gene is required to show up the brindle colouring when the brindle gene (Abr) is present on the A locus. On a small number tested, the Bus Dubh pattern (black muzzle ring) appears to only show up on e/e animals, although the location of the Bus Dubh gene has not been uncovered.
Wild Type ( E+/E+, or E+/e)
The actual gene that dilutes red and black coat colour in Highlands (SILV del or DH as I have named it for simplicity here) has only been uncovered in the last few years by Dr Sheila Schmutz and her paper on this should be released in the next 12 months.
As per the Genetic Make-Up table below, one dilution gene (DH/+) makes a red animal yellow, and a black animal dun. Two dilution genes (DH/DH) makes a red animal white (or cream as some say) and a black animal silver dun. This is all pretty straight forward and was suspected for some time. Some breeders have trouble distinguishing white from silver dun. Silver dun Highlands have grey pigment on their nose, and black pigment in their hooves and tips of their horns.
At the moment, all white animals have been DH/ DH on DNA tests performed, and so must have received a dilution gene from each parent (that is neither parent could be red or black). A white animal from a red or black parent suggests that there may be some other gene related to white as has been shown in other species. This may be possible in Highlands and I would be interested to hear about any of these calves as well.
When researching the gene that dilutes Charolais (DC) to white the authors found a gene at the end of chromosome 28 that appeared to soften any colour even further (makes a red animal light red, nearly yellow for example) and this may well be present in Highlands and could explain some of those 'in between cattle'. They also postulated another gene that may darken coat colour slightly.
Brindle patterns in dilute red animals (yellows and whites) are exceedingly rare and so it appears that the dilution gene may mask these. Yellow brindles appear to occur occasionally though. These are another colouring where more work needs to be done & I would be happy to discuss these with anyone further.
This has been shown to contain a dominant brindle gene in Highlands (Abr) and one or two of these will see an animal with black stripes to varying degrees on a red back ground. Two of the animals in the study performed last year however did not fit exactly with this and so it is suspected that there is another gene that contributes to this pattern in Highlands. As mentioned earlier, at least one copy of the E+ gene must be present at the E locus for the brindle pattern to be seen.
There are some amazing colour changes that can occur in nearly every Highland coat colour but is most dramatic in black and dun animals. Many black and dun calves are born a 'chocolate', a colour that slowly is lost by 8-12 months where their underlying black colour becomes more apparent. The amount of pigment in the muzzle is the best clue here.
Black calf born black
Dun calf born grey
Silver dun calf born light grey
Black calf born ’chocolate’
Dun calf born ’chocolate’
Even yellow and red calves can look the same when born and can add to confusion in coming up with a colour to register them. The reason behind this colour change in many of our Highland calves is not known – there may be some protective adaptation in all being born a rusty red colour – for camouflage amongst the heather perhaps?