Wednesday, 26 August 2015

Poodle diversity study

The results of the poodle genetic diversity DNA study undertaken by the UC Davis last year have now been published and you can read the paper here. My own dogs' DNA and that of a number of other dogs of uncommon bloodlines I organised in the UK were sent to the researchers.

Two 'poodle people' Natalie Green Tessier, the organiser of the study, and Lynn Brucker, the programmer responsible for the Poodle Health Registry, are authors on the paper. This is extremely unusual in the scientific world and not something I've ever seen before. Natalie and Lynn I hope will be very proud of what they have achieved.

EDIT: Since this publication came out, due to the somewhat 'dramatic' title and some phrasing in it, some people with no interests in the breed, who unfortunately it seems lack the capacity to understand it or investigate the work that went into it, have been trying to use it for scaremongering. I feel for this reason it is necessary to clarify that the research paper is about the incidence of two autoimmune diseases, and the reason these autoimmune diseases were studied were partly because of funding from poodle clubs wanting information on possible ways to reduce their incidence and also because this is the specialist area of the main researcher Pedersen, and research groups need publications to increase their prestige and attract funding -- that's just the nature of research. The main thrust of the study was to develop a test that poodle breeders can use to help inform breeding decisions to preserve genetic diversity in the breed and ensure long-term viability of the gene pool. The importance of this test or how it is used was not really touched upon in the paper, because it's not the sort of information that is published in scientific journals, and it's up to the laboratory that developed the test and breeders to disseminate this information (see my earlier posts about use of genetic tests, and also Natalie's presentation).

To put things into perspective, most of the autoimmune diseases mentioned in the introduction to the paper have indeed been found in poodles, but they do not seem to be particularly common. Indeed, they occur in dogs generally as a species, regardless of breed, and the risk to poodles to my knowledge (as a person with an interest in the breed, who researches bloodlines) is probably no more than for any other dog. The two diseases the paper studies, sebaceous adenitis and Addison's disease, do seem to occur more often in poodles than they do in dogs taken as a whole. Sebaceous adenitis is a skin disease that can occur in any dog, but it does seem to occur more in poodles and certain other breeds. However, in recent years its incidence seems to have decreased, which is probably a lot to do with breeders testing dogs with a skin biopsy for SA as a precaution, so we can identify dogs that are affected and know to breed lines where it has occurred carefully and effectively select away from it. If you are buying a poodle puppy, it's important to see evidence of this testing from the breeder -- although since dogs affected by the disease normally show symptoms by middle age, and the biopsies tend to cause scarring, this is probably less important in older breeding dogs tested clear in their youth, or dogs from ancestors who are intensely tested and consistently clear, so long as in these cases the dog has never shown any signs of the disease.

Addison's disease is a more common disease generally -- quite possibly it is the most common autoimmune disease in all dogs. It is, however, a very controllable disease if it is diagnosed promptly, and affected dogs can live a normal life with the help of medication. Whilst it is unfortunate that poodles are more at risk than other dogs, it does often happen that particular breeds have increased risk of certain ailments (just as some ethnicities in humans have increased risks of, for example diabetes or sickle-cell anaemia) and it is hoped that by assisting with research such as this, it may be that a genetic test is developed to help us breed away from it, which is the holy grail of this sort of work. Hence, DNA from lots of poodles affected by these diseases were sought out and sent in to the study, and the researchers so far as I know will still process them free of the usual charge. This is why data from poodles with these conditions, to compare with unaffected poodles, is well-represented in the paper -- the proportion of affected to normal poodles is not at all representative of the population as a whole.

The study did find some interesting information about these disease, for instance, that both Addison's and SA seem to occur mostly in the main group of genetically similar dogs, and that SA (but not Addison's) seems to be more common in more homozygous dogs, which means using the test to breed towards more heterosis along with information from biopsies should hopefully further decrease the occurrence of this condition in the breed.

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