The Importance of Accurate Genetic Records and Reporting   Leave a comment

I want to write a bit about something that is very much in the front of my mind – genetics. This is not so much another primer on the different types of rat genetics, how the different genes interact, what they are, etc. There are plenty of resources out there for that already. This is more a statement on the importance of ACCURATE recording of genetics.

This came up after I found an article someone wrote where she actually proposed ignoring genotype altogether in favor of just trying to make other genes look like what they wanted. In this case, she argued that its hard to get good points on a himalayan rat (ch/c) where its easier to get them on a siamese (ch/ch), and suggested that better ‘himalayan’ rats could be gotten by selecting for siamese with lighter coats and less shading. Her other argument was that himalayan is homozygous in rabbits, and therefore should be in rats as well.

There are several problems with this suggestion. While this MIGHT actually help improve the points, its not actually making himalayan rats, its just making siamese that ‘look like’ himalayans. Breeding, selection, and improving of the species is more than looks, its about selecting the proper type of animal to improve the traits. Rather than spending time selection for poor siamese, with a lack of shading, etc, the energy could be better used to select for better points on true himalayans.

Using the argument of rabbit genetics is completely absurd. Rabbits are not rats, they aren’t even rodents, and there is no real relation between them. We certainly don’t have the same colors and markings as rabbits do – dutch and the like, nor do they have the same things rats do. There is absolutely no logical reason to believe or expect a similar phenotype to act the same way. I mean, using the same argument, we could argue that all ‘himalayan’ animals should resemble the cats – short faces, long hair, etc. But we recognize these are different species, and function in different ways. Just as brindle stripes in dogs and tabby stripes in cats don’t function with the exact same genetics, we have no reason to expect that coloring should act the same between rabbits and rats. Even mice and rats have huge differences in the colors and markings – the genetics of one species are not going to be the same across all species, and there is no reason to try to force them to conform.

One of the biggest issues is the long range problems this would cause though. In the short view, maybe there would be rats that look himalayan with darker points, therefore doing better in shows. But breeding needs to look past this. What would this mean for the future? It would make the pedigrees nearly impossible to figure out. When someone is looking 5 years down, 10 years down the line, at the rats – who may have had offspring sent to another breeder, who bred them and send offspring elsewhere, making them FAR removed from the original person who started this idea – what will they see? All those people will see is the listing ‘himalayan’ in the pedigree. What is totally absent is the note that its a SIAMESE bred to LOOK LIKE a himalayan. This can cause many difficulties to the people trying to follow the pedigrees later.

If a breeder were to get these ‘himalayans’ they would have no way to differentiate them from ones that are GENETICALLY himalayan. Looking at their pedigree, if the original breeder started listing light siamsese (ch/ch) as himalayan (ch/c), and the people who followed them with their rats did the same, then the pedigree would claim several generations of himalayan (ch/c). Someone getting one of these rats, and trying to outcross it to their lines would have problems. Crossing it to a different line of siamese to try to produce siamese and himalayan babies would only give siamese – and likely siamese lacking proper shading, etc. On the other hand, crossing it to a true albino (c/c) would give only REAL himilayans, and no PEW offspring, as would be expected with a breeding to a himalayan. While these methods could be used to determine what they are actually working with, they are test breedings that SHOULD be unnecessary with correct labelling, based on the GENETICS and not just the looks.

To take this to a different example – I want to work with agouti. What if someone decided to take something like russian blue agoutis, and when they are particularly dark, just call them ‘agouti’ because they are darker than RBA normally is. Lets say they decide to keep breeding those as ‘agouti’ and registering them as such. Now, for my line, I want to try to remove the carried recessives, so I want to look for straight agoutis to use. This will also help with my fawns, trying to get them to be straight fawn, and not russian fawn or other dilutes. If I got one of these mislabeled RBAs, and looked at their pedigree, I’d see lots of agouti, with no russian blue agouti listed. Lets say I bred it to a black rat I had to try to have a litter of black and agouti, and then bred 2 of those together, etc for more agouti. Eventually I’d be seeing russian blue pop up, and there would be NO explanation for it by the pedigree. This could seriously complicate my ability to create a line clean of russian blue. Also, since russian blue is so prevalent in the rats I will be likely to start with, if I wanted a non-russian blue rat to cross in to start extracting it, these ‘fake’ agoutis would cause me major setbacks, as no matter how much I use them, I’d not ever get anything but RB based colors and carriers of RB from them.

On the other side of the same sort of thing, lets say I took all my light, washed out looking agoutis and started just calling them russian blue agouti, even though I knew they didn’t have the russian blue gene – because I thought they LOOKED more like RBA. Lets say I register them as such. Now…lets say at some point in the future, someone is trying to create something, say, russian silver, and they have american blue, but no russian blue. They manage to acquireee one of my ‘russian blue agouti’ rats, and have hopes to breed them to their american blues to try and get russian silvers in a couple generations. Unfortunately, no matter how many times they use these fake russian blue agoutis, and how many of their offspring with american blues they pair up, they will NEVER get russian silver, because the rats aren’t really russian blue agouti, they are just washed out agoutis. This could be a major blow to a program that is trying to salvage a line or recover a certain genetics, if the rats they have are incorrectly labeled in the pedigree.

There can also be a problem where a ‘mystery’ color shows up, because the pedigree doesn’t actually list that they carry it at any point in their history. Without having accurate records, it can be difficult to impossible to figure out what is showing up in lines.

This same sort of thing can be applied to ANY color. Labeling by phenotype at shows is one thing, and a commonly practiced thing. But it is vitally important to not only the rats we have now, but to future generations to ACCURATELY register and label rats based on their GENETICS, so that correct and informed decisions can be made about pairings involving them and their descendants.

There are people out there who will say its silly to get upset about colors, because good breeders should be more concerned with health and temperament than color. This is only partially true. A good, responsible breeder should absolutely be MORE concerned with health and temperament, and these should trump other considerations and be a given, not an optional thing. However, a good breeder breeds for the WHOLE rat, not just a couple aspects. So while health and temperament are the most important considerations, selecting for coat, color, markings, ears, etc is also important in helping improve the species overall, and breed better rats. Its impossible however, to select for the whole rat when genetics are unknown. With incorrect pedigrees, that are mislabeling colors and misrepresenting the genetics of the animal, its a major step back for trying to make the BEST possible selections and pairings to really improve the rats.

The other risk is that slips in recording accurate color genetics information could be the first step into problems with recording other information. We already see a huge lack of updates regarding lifespan, health information, etc in registries. But when people start thinking making up information or inaccurately representing their animals as far as color is acceptable, this can progress to not only a lack up updates in general, but a problem with having to worry that the updates we DO see are truthful and correct. For myself, I think its importance that breeders (and their adopters! Adopters hold the keys to really encouraging proper breeding – see this great blog post ) hold themselves and those they work with to the highest standards, which means accuracy in ALL their record keeping.

Pedigrees are supposed to exist to give us accurate and complete information about our animals. Ideally, this includes date of birth, date of death, cause of death, any notes on health or temperament, etc. It should also include genetically accurate color, coat type, ear set, etc. When people make up ‘facts’, or worse, intentionally misrepresent them, as suggested by the person who said light siamese should be called himalayans, it destroys the function of the pedigree and undermine the efforts to keep accurate records and make the best choices for the species.

The take home message to all the breeders out there – please, for the love of your rats and the future of the hobby, keep complete and accurate records, and follow the true genetics, not just the looks, to help yourself and others make the best choices and progress for the species.


Posted June 25, 2011 by betuana in Uncategorized

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