Coat Colour. Lakeland Terrier

Transcription

1 A Discussion of Coat Colour Genetics in the Lakeland Terrier Chapter 6 Blue By Ron Punter

2 Blue: G gene is produced by an extra gene modifying the black pigment, it is not an allele on the same series as black. Generally when Blue is stated in a breed standard it is assumed to be genetically d,now known to be a variant of the melanophilin gene (MLPH) which produces abnormal distribution of pigment in the hair shaft. It is recessive and when on both chromosomes the effect is to change black pigment to a lighter shade. Dogs with dd (dilute) alleles are blue with blue noses at birth and keep the colour without progressing to grey other than by normal ageing over their life time. It effects all eumelanin. pigment not just the coat. dd will also interact with liver (brown) to produce the pale colour sometimes known as Isabella. there is a commercial genetic test for d available. When Blacks were reintroduced into the UK some blues were produced but not born blue turning blue (though some of them did so quickly) and this is my comment from an article at the time: A recent breeding result has emerged which might indicate that even the Nordic Blacks and Blues are not of the type assumed by geneticists such as Robinson and laid out in my chart in the previous year book. The production of a Blue from a Black mated to a UK Black and Tan/ Grizzle (which is unlikely to carry recessive blue b ) might indicate that like others we know of in the world they are of the Kerry Blue type. As is very evident in Kerries, which are generally born black, the greying effect is very variable and at one extreme can still appear as Black. Robinson says it s a moot point whether or not the gene should be regarded as a semi-dominant or a recessive. In this case it might be semi-dominant in the sense that it was expressed in an offspring though only the black parent carried it but recessive in the sense that neither parent obviously displayed it. If this result proves to be the norm then it s interesting to Page 2

3 speculate that Black and Blue Lakelands did come originally from the Lakeland/Bedlington cross that writers in the 1930 s commented on. It s also worth noting that the Wire coat is dominant and the softer coat recessive and so can be carried (though it s been suggested that a carrier might tend to rather long hair.) Robinson says of the Bedlington: examination of the colour of the puppies is the only sure means of discovering their genetic nature. To attempt a similar classification with the adult colouration is to court mistakes. - It s the colour when the puppy has dried out after birth he is referring to. Quote from another article of mine commenting on breeding out Bedlington genes in the UK: whenever there was a Lakeland with a fluffy top knot the old breeders would say it s old Tommy Dobson s Bedlington coming out but the more I learn of Bedlingtons the less I think they have anything to do with the lineage of Lakelands. Bedlington pups are born dark brown or jet black, the muted colour of the adult is a product of the coat type, scissoring and the greying gene. The first Bedlingtons were mostly liver colour, any of these solid livers mated to a typical black and tan or grizzle Lakeland would produce mostly black in the first generation with the possibility of a Liver or Red but no Black and Tans or Grizzles. If typical Bedlingtons had been used early in the breeding of Lakelands from Fell Terriers then solid colours, especially black, would have been common rather than unusual. The Bedlington is one of the longest established terrier breeds, the head, ears and general type of Bedlington are apparent in the first champion bred in 1870 (though the roach back came in later.) There isn t really anything about the unique Bedlington breed that you would want in a Lakeland so it would be more a case of breeding out any Bedlington like characteristics rather than introducing Bedlington into the indigenous Fell Terriers of the Lake District. Since writing the above it has become apparent that blue in Lakelands imported back into the UK after 70 years absence is very like the blue in Bedlingtons and not the dd recesive gene. Page 3

4 My current working assumption is that most Blue Lakelands we know of are not dd but G. G does not effect Mask, Some Kerry Blues are a striking example of this - their main coat may turn to silver while leaving the hair on their muzzle solid black. Might seem strange that Black dogs can also have a separate gene for black mask Em (M264V) on the MC1R locus,a gene on the recessive red series dominant to e so is not present in an ee Red Lakeland. Red (or Cream) dogs with masks such as Pugs definitely indicates that the red results from the Ay gene not ee - hope this makes it clear that Em e will not produce a red dog with a black mask of it s self and the e will just be carried but even just one Em allele will produce mask in other genotypes and so cannot be carried though it wouldn't be obvious in a solid black. Currently we don't seem to have A y reds in the UK Lakeland gene pool but we might have in the past. Mask can find expression in Saddle pattern (as you see in GSD s.) Mask was sometimes expressed in Irish Terriers which are all A y but it is not liked and selection is for a clear face because the standard says Black shading highly undesirable. I think it would equally have been selected against in A y Lakelands so we don't see it in saddle pattern Lakelands whose faces tend to clear when they mature as Irish are expected to, a black face on a Bedlington would not be acceptable so Mask could not come with the blue from them. Whilst it s just possible that Mask might have been hidden in the Nordic Blacks everything considered I think it unlikely so taken all round don't think we will see Blue Lakelands with black Mask. If it is hidden in the Blacks it could be crossed back into the Saddle Patterns as well as coming out in Blues which would be untypical of the Lakeland as a breed. It s suggested that G does not effect tan to the same extent that it does black but have seen pictures of some strange looking Blue and Tans and doubt you will see a Blue and bright Tan Lakeland (like Yorkshire Terriers.)It will of course effect liver (as seen in Bedlingtons) as does dd. A further complication is that most Black and Tan Lakelands are not a strong black like Welsh Terriers and in the past this led some kennels, for example Miss Morris (Kelda) to register such dogs as Blue and Tan and only the darker ones as Black and Tan. These lighter ones are not born the distinctive dd blue, although it s tempting to speculate if this is the G gene more likely it s a case of Page 4

5 lack of pigment in the undercoat. Colours registered in the stud book can be very confusing for geneticists even to the extent of some breeders calling liver blue! So it s another moot point how black is black? Looking at dog genetic sites on the web G is generally said to be a simple dominant and GG or Gg will both produce Blue (Grey). It s often ignored that the degree of greying is very variable and might be stronger in the heterozygote. As Robinsons says it could be considered semi dominant or even recessive, as we have seen, and he implies, it s not following mendelian principles. These Miniature Schnauzers were born almost solid black. Geneticists tend to steer clear of Schnauzers, (Robinson says some specimens defy ready classification ) so I don't know why I m commenting but they look to have the Chinchilla g e ne ( o r e xt r e me pheomelanin dilution) in combination with the greying gene. Tan points and bands on a Salt & Pepper are converted to the silvery or white colour mostly by the chinchilla gene whereas the black in the coat is effected more by the greying gene. This paragraph is just to indicate that the greying gene by itself would not produce white tan points and a blue saddle. When Bedlingtons get an injury the hair grows back black and can take a long time to turn blue again. I have seen a photograph of a blue Poodle with a sizable black patch said to be due to a rabies vaccination beware microchips require a very large needle! Page 5

6 Young Bedlington whelps solid black but will turn blue gradually as they mature note the white foot on one - will not be discernible latter as it will blend with the mature coat. I will discuss white feet in Lakelands elsewhere in this book. This Staffordshire Bull Terrier is a good example of the d d gene. There really is no mistaking the born blue in a whelp.. Note the well pigmented but definitely blue nose even the toe nails are blue. A recessive red that has d d allies will have a blue nose whilst a red D d will carry blue without displaying it even in the nose. On the first chart of coat colours published a couple of years ago I had e e d d as a possible type but the latest research indicates that dd will not effect the actual coat of a recessive red and observations that it does effect red apply to Ay dogs. The dilemma now is whether to leave it as a type because of the blue nose or to remove it because the dd probably doesn't exist in Lakelands! Page 6

7 Isabella Lilac d d b b Whilst it appears that the dilution d gene probably doesn't exist in Lakelands the other gene that is sometimes thought of as a dilution the brown b certainly does, the colour know in Lakelands as liver. The two dilutions in combination produce the Isabella colour ( Lilac in g e n e t i c t ermino lo g y) which is the typical colour o f t h e W e i m a r a n e r often aptly described as the Grey Ghost. Complimentary to the coat they have a lightblue/ liver nose Weimaraner Puppies Just to state the obvious-without the two diluting genes a Weimaraner would be solid black. Brown Dilute Eumelanistic Colour B- D- Black B- dd Blue bb D- Liver/Chocolate bb dd Isabella Chart showing combinations of dilution genes The greying gene G will effect liver coat though will not effect the nose so an adult Lakeland looking similar in colour to an Isabella but with a liver nose could be produced by mating a Liver (b b g g) to a Blue carrying liver (G- Bb) or two Blues both carrying liver or Black to a Blue both carrying liver. At least one parent should be G but as discussed it s not completely dominant and can be passed on by a black dog. Page 7