Rat Health Care & Information
Black Eyed Varieties
Black Eyed Cream - the continuing story...
It has been a while since anyone has updated the progress on the ‘dark eyed cream’ gene that was found in Edinburgh University in Scotland back in 1998 and was initially reported in Pro-Rat-A by Claire Jordan (107, page 9-11), so since the last article on creams was back in 2000, it seems high time for an update on how the breeding and genetics has developed. I do not pretend to be a genetics expert, and I am sure there will be a few genetics experts within the club will rip my theories to shreds!
After the initial breeding in Scotland by Donald Dickson, Veronica Simmons made a day trip to Edinburgh to collect a trio of black eyed creams from Claire Jordan so that breeders in the south could work on the variety too. She and Joan Branton bred several litters and were joined later by of Melanie Goulder and they did some excellent work on breeding and improving these lines ‘down south’. Sadly, Joan gave up breeding and Veronica and Melanie eventually both decided to concentrate on their original varieties and let others continue working on the black eyed creams, Siamese and Himalayans. However no one really took them on with a vengeance and there was a point where the genes were nearly lost. A few people who had dabbled with them stopped because there were some temperament problems noted in the lines, and it meant no one seemed to be focusing on them. Aside from Don continuing breeding a few litters of creams before retiring from breeding rats a couple of years back, the other Scottish breeders continued with the ‘taupe’/biscuit rats and their Burmese.
A couple of years ago I got my first black eyed Siamese buck from Veronica to use with my Burmese line. They were never intended to be my focus, but they did make it easier to home the non-Burmese rats in any litter I had…
Over the years there have been a number of breeders who have worked with or dabbled in the breeding of these black eyed rats and as more outcrosses have been done, it’s become clear that original thoughts on the genetics of them being on the c (colour) locus are wrong. Basically it has been proven by a number of matings now that there just is not enough room on the c locus to have all the varieties we are seeing from the litters. Current feelings are that the black eye gene behaves on the c locus in a similar way to how pearl works with mink, although there are a few final test matings needed to confirm this. The other possible is that black eye is a straight forward dominant that shows itself on any rat that doesn’t already have black eyes – for example it would be needed to be proved whether or not it works on the p locus as well or not. Below using the litters we have had, I will demonstrate the findings and summarise what else we have to prove.
We now appear to have three clearly different shades of rat from working with mixing these black eyed cream rats with Siamese and Himalayan lines over the years. We see rats that are pretty well shaded Siamese with black eyes, rats that look like Himalayan with only the points and also black eyes and the original creamy white version with black eyes (now known as Ivory in the new varieties standards). (We also have a darker cream colour with black eyes which I will touch on later in the article)
Many of the original breeders of the black eyed rats seem to generally have worked on ‘making more’ and improving the shading and generally only really breeding with Siamese, Himalayan, PEW or known carriers. Black eyes proved to be dominant over the c locus as it was reproduced directly by matings with the first (and only) cream buck – The Milkman – at that time to c locus rats. While some of the odds often looked a bit weird and even by the 2000 article (PRA 115) by Claire Jordan she was indicating that there was some ‘flies in the carefully constructed genetic ointment’ – things like some people getting all black eyed kittens in the litter while others got some black eye and some red/ruby eye – it was just assumed by most that this was nothing more than ratios playing games, but one of the key litters that really made a few people think was a litter bred at Shunamite Stud from an agouti x black parents.
The agouti dam had an Ivory parent so hence the black eye was in there and the black parent had Siamese rats behind him but definitely no chance of anything black eye in there. The litter contained a number of varieties including both a black eyed and a red eyed Himalayan which with 2 alleles on each loci just can’t happen if black eye was on c. Ignoring the other genes that were carried and only looking at the c locus specifically, the black parent was most likely a/a C/ch and the agouti parent could from original theories have been A/a C/c or A/a C/ce. If the Himalayans had all been black eye or red eye, then that would have been possible, but getting both black eye and red eye makes 3 alleles on the same locus, which is just not possible! From this litter, black eye must be either dominant working with the c locus (think similar to the way pearl works with mink) or dominant but hidden when the eyes are already black or dark. (For example purposes only I am using ‘Be’ for black eye when giving genetics.) If you applied ‘Be’ to the equation for this mating, the sire would be a/a C/ch ‘be/be’ and the dam would be A/a C/c ‘Be/be’ and did the maths on the genetics, it works! – You should get half red eye and half black eye in the Himalayans as they would be ch/c Be/be (black eyed Himalayan) and ch/c be/be (red eyed Himalayan).
Many more litters have proved to give much the same results – a particularly humorous one was when Matthew Creaney took a Russian dove doe from me (who did have a chance to carry c and ‘Be’ from great-grandmother (agouti above) and was assumed to be USA mink based) and mated to an English mink roan and had a surprise when he got both black and red eyed Himalayans and every rat in the litter was mink based, particularly when he didn’t expect the two minks in the rats to be the same mink so had expected a whole litter of blacks…
The main thing left that has not been confirmed by anyone that we are aware of yet is whether it is possible to ‘make’ a black eyed champagne or silver fawn. When there are a number of dilutes in the equation on the black eyed rats, it has been noted that the eye colour can be dark ruby – notable on Russian dove points, mink points and blue points – so testing for black eyed topaz and buff (RED) isn’t really going to be that conclusive. No Siamese or Himalayan breeder working towards improving the points is going to actively put the pink eyed gene (PED) into their lines so this has to be a special effort for proof purposes. Champagne has been noted several times along the line in breeding without the eyes being black, (see Claire’s comments in PRA-115 on p13 regarding blue champagnes with red eyes and Chillingham – a probably silver fawn Himalayan who faked looking like a PEW) but as far as I know, no-one has really truly tested whether it is possible to ‘make’ a black eyed champagne.
Whether we assume black eye is only having a relationship with the c locus or has a relationship with any pale eyed rat, we have proven that it’s possible to have homozygous ‘Be/Be’ black eyed rats, where the offspring are only black eyed. There appears to be no health implications on producing these rats, and from tests, it appears that other varieties can be homozygous black eye – example of a black rat carrying Siamese which when mated to a ruby eyed Siamese produced all blacks or black eyed Siamese – black must have been a/a C/ch Be/Be, but because the black eyed rat already has black eyes, no matter which theory is subscribed to, it’s impossible to visually see if that rat is a ‘Be black’.
It has also been proven that Ivory can be agouti based and not affect the very pale creamy white coat colour, which takes us onto the ‘creams’…
This darker colour appears to have darker cream ticking on a yellowy beige colour and is very subtle – these have demarcation lines showing that they are almost certainly A/- rats.
There were reports of more yellowy rats early on, and it seems what we are now calling ‘cream’ may have been lost for a while or just not noted (you cannot easily tell whether they are cream or ivory until they’ve had their 5-7 week moult, so there is a chance they’ve been homed before it’s known…). Also, because very few people have been breeding for the actual ivories and working on Siamese/Himalayan instead, they would have outcrossed more to black selfs to improve the shading and points, the agouti side of things may have been lost, and the self version of this appears like a very well marinated yellow!
About 15 months ago, Julie Oliver noted a darker cream colour turning up in one of her litters from PEW (Valhalla Kusu) x Ivory (Valhalla Thor) at around 5-6 weeks old. She kept that sole cream doe kitten (Valhalla McVitie) and bred back to Thor and got more and also repeated the first mating with Kusu x Thor for an American export and got more in there as well. Currently Julie has three creams, I have one (Valhalla Neptune), one is in a pet home and one is with Elisabeth Brooks of Spoiled Ratten in the USA.
Test matings done to date towards the cream data since they ‘reappeared’:
Below are the test matings that need to be done to prove more of what is going on with the creams:
Thankfully a number of breeders are now working with the black eyed genes so hopefully more data will become available soon, so watch this space for more information. If you have any extra additional breeding information to add to the ‘pot’, we would love to hear from you.
Other things noted in breeding
Quite a number of the people breeding Burmese have tended towards using the black eyed Siamese/Himalayan rats in the breeding probably as much as anything to aid the homing of the non-Burmese kittens in the litter as sadly ruby eyed Siamese do not seem to be as popular with pet homes as the black eyed ones. In order to breed black eyed or ruby/red eyed Siamese or Himalayan to the variety standard they should be considerably different with Siamese having dark shading and Himalayans only having points. The best Burmese shade seems to be ‘made’ from using Siamese or Himalayans that are borderline between the two so either lightly shaded Siamese or slightly shaded Himalayans. This effectively means that Burmese breeders are not actually doing anything to help improve the Siamese/Himalayan lines and we see a lot of mediocre Siamese and Himalayans because of this. If you are working with either eye coloured Siamese or Himalayan you are better sticking with the one variety and working to improve that and not mixing and matching with all the other varieties.
Pro-Rat-A 107 p9-11
NFRS Standards related to the black eyed varieties: -
Siamese (includes both eye colours)
Body colour to medium beige, gradually and evenly shaded over saddle and hindquarters towards the belly, being darkest at the base of the tail. There should be no white or very pale areas anywhere on the body, feet or tail. Tail colour to extend down the length of the tail. Belly to be light beige. Points to be rich dark sepia and shade evenly into the body colour. Eyes black or ruby.
Black eyed Himalayan (currently in New Varieties)
Body colour to be white with beige points on the nose, feet and root of the tail. Beige shading not to extend above the eyes on the face, beyond the elbow on the forelegs or beyond the hocks on the hindlegs. Ears and tail to be lightly pigmented. Eyes Black.
Ivory (previously known as black eyed cream) (currently in Guide Standard)
Body colour to be very pale creamy white all over with no odd coloured hairs or patches. Ears and tail to be pink. Eyes Black.
Cream (currently in New Varieties)
Body colour to be a rich 'Devonshire' (warm) cream colour with no odd coloured hairs or patches. Ears and tail to be pink. Eyes: black.
Article originally published in Pro-Rat-A written by Estelle in 2005
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Last modified: February 02, 2009