Frequently Asked Questions (FAQ)
I know my dog has an inherited disorder but it does not appear in the listing on LIDA. Why?
The present LIDA website represents phase I of the LIDA project. LIDA displays listings of breed predispositions sourced from the US, because there are no Australian data available at present.
Happily, we can report that more than 230 veterinary practices across Australia have written to us to confirm that they would like to report their diagnoses when LIDA Phase II commences.
What is being done to obtain estimates of prevalence of inherited disorders in Australian dogs?
Associate Professor Paul McGreevy and colleagues have prepared a plan for a national project that will provide continually-updated estimates of prevalence. This project is called LIDA Phase II
The results of the research will allow:
- Potential purchasers to make informed decisions when buying companion animals.
- Veterinarians to benefit by being able to provide clients with local current data and by being able to learn from the profession's pooled data.
- Breeders to recognise which unwelcome traits are increasing and which are being successfully reduced.
The major snag is that we need to raise $170,000 to support the project for the first three years.
The really good news is that in Australia, more than 230 practices have formally agreed to contribute data, and Dogs NSW have kicked the project off with a pledge for $30,000.
Thanks Dogs NSW!
How can I help the LIDA Phase II Project?
If you are interested in making a donation to help further this project -
- please contact the Veterinary Science Foundation Director on 9351 8024;
- complete the donation form(pdf), or
- alternatively make an online donation.
Why are the data in LIDA not Australian?
There is currently no system for collecting information on the true prevalence of inherited disorders in Australian dogs. LIDA Phase II is aimed to change that.
How has LIDA been received nationally and internationally?
LIDA has received the following awards:
- 2008 National (Australian) Teaching Award - Pearson Education UniServe Science.
- 2009 British Society for Animal Science- RSPCA Award for Innovative Developments in Animal Welfare.
- 2009 Universities Federation for Animal Welfare (based in the UK) - Companion Animal Welfare Award.
All prize money from these awards has been channelled directly into the LIDA fund to permit the launch of LIDA Phase II.
What is inbreeding?
Inbreeding is the mating of related individuals, i.e. individuals that have one or more ancestors in common.
What is close inbreeding?
Close inbreeding is the mating of close relatives. The closest form of inbreeding in domestic animals involves matings between full brothers and sisters (full sibs) and between parents and offspring (collectively called first-degree relatives). The next most close form of inbreeding involves matings between grand-parents and grand-offspring, between half brothers and sisters (half sibs), between uncles/aunts and nephews/nieces, and between double-first cousins (collectively called second-degree relatives).
What is linebreeding?
Linebreeding is a term commonly used to describe milder forms of inbreeding. Typically it involves arranging matings so that one or more ancestors occur more than once in a pedigree, while avoiding close inbreeding. Because many breeders apply the term “inbreeding” only to close inbreeding, we shall refer to inbreeding/linebreeding in answering other questions.
What is the effect of inbreeding/linebreeding?
On average, the effect of inbreeding/linebreeding is an increase in the prevalence of inherited disorders, a decrease in viability and reproductive ability, and the loss of genetic diversity (i.e. decrease in genetic variation). Collectively, these effects of inbreeding/linebreeding are called inbreeding depression.
How is inbreeding/linebreeding measured?
The coefficient of inbreeding (CI) measures the extent to which an animal is inbred/linebred, compared with animals in a reference population that are assumed to be unrelated and have zero inbreeding. Typically the reference population is the earliest generation of animals for which pedigree information is available. The CI ranges from 0% (equivalent to the reference population) to 100% (completely inbred). It is important to note that the CI is NOT an absolute measure. Instead, it is a relative measure, i.e. relative to animals in the earliest generation of a pedigree. However, at the top end of the CI scale, being 100% inbred has an absolute meaning: the animal is completely inbred.
How many generations of pedigree are required to calculate the coefficient of inbreeding (CI) of an animal?
CIs can be calculated from two or more generations of pedigree information: CIs calculated from two or three generations show the extent of recent inbreeding; CIs calculated from a larger number of generations include longer-term inbreeding as well as recent inbreeding, and hence tend to be larger. The main thing to note is that in order to compare CIs, they must be calculated from the same number of generations of pedigree information.
What are the characteristics of an animal with 100% CI?
An animal with a CI of 100% is equivalent to a member of an inbred line. Such lines have been produced in laboratory animals such as mice, but only after losing many lines (typically more than 90%) due to inbreeding depression. In animals with 100% CI, every section of every chromosome has two identical copies of the same segment of DNA (in technical terms, such animals are completely homozygous). This means that every sperm and every egg produced by such an animal is identical. Because of this, animals with 100% CI are said to be true-breeding, although in reality there is still variation in their offspring, due to new mutations and variation in non-genetic factors.
How inbred are pedigree dogs?
We are currently conducting analyses of Australian pedigree files to answer this question.
Until we have the results of this Australian study, our best guide is a recent analysis of 2.1 million pedigree dogs in the UK Calboli et al., 2009, Genetics 179, 593-601, involving the 9 most numerous British breeds, representing over a third of all dogs in the Kennel Club’s electronic pedigree records. This is the study featured in the documentary Pedigree Dogs Exposed. Based on 6 and 7 generations of pedigree, the average CI across these nine breeds is 4.4%. This means that, on average, the most-numerous breeds in the UK are 4.4% along the way towards becoming inbred lines, compared with animals that existed 6 and 7 generations ago (around 33 years ago). In other words, the average CI in the nine most-numerous UK breeds has been increasing at less than 1% per generation.
What range of CI was found in the UK study?
The average breed CI in this study ranged from 2.4% in Labrador Retriever to 7.3% in Rough Collie. For individual dogs, the maximum CI ranged from 32% in Akita Inu to 50% in four Boxers. This indicates that the most inbred of all the 2.1 million dogs in this study are half-way towards becoming an inbred animal, i.e. they are still a long way from being true-breeding. At the other extreme, the UK study showed that more than 90% of dogs in the nine breeds were the result of matings less close than second-degree relatives.
What would be an acceptable/good CI range to strive for?
There is no acceptable level of CI below which there is no risk. The deleterious effects of inbreeding (described in a previous answer) increase in magnitude as the CI increases from 0%. Because of this biological reality, breeders should be aiming to arrange matings so as to minimise the CI of offspring. In other words, breeders should be aiming to arrange matings between animals that are least related.
I know of a dog with a relatively high CI and it is perfectly normal. How can this observation be consistent with inbreeding being deleterious?
Animals with high CI that appear to be healthy do arise from time to time. From the creation of inbred lines in laboratory animals, we know that it is possible to create such animals with a CI of 100%. However, the evidence from the creation of these lines shows very clearly that the chance of creating such an animal is extremely low; and that in order to create such an animal, many thousands of animals will be born with serious health and reproductive problems.
In a classic case of the creation of an inbred line of mice, only one of 20 lines survived; the rest went to extinction due to inbreeding depression Bowman and Falconer [1960] Genetical Research 1, 262-74. Furthermore, detailed examination of completely inbred animals often reveals abnormalities that are not evident to the naked eye.
Linebreeding to a champion animal surely increases the chance of me creating another champion. Isn’t this a justification for linebreeding?
The first statement is correct. However, there are two problems with this approach. First, there is inbreeding depression which, as seen in other answers, increases as the extent of linebreeding increases. Second, even intense linebreeding still leaves breeders far short of recreating the champion, meaning that the results of linebreeding (neglecting inbreeding depression) are extremely variable. Furthermore, unless the champion was far more inbred than even the most inbred of pedigree dogs, the chance of a dog that is linebred to the champion actually being a “clone” of the champion is very small. In other words, the chance of linebreeding achieving its aims are frustratingly low, whereas the chance of it creating inbreeding depression are very high.
To what extent are dog breeds losing genetic diversity?
The best guide to this is the change in average CI over generations. Until we have the results of the Australian pedigree analyses, we must rely on the results of the UK pedigree analyses, which (as mentioned in answer to a previous question) showed that average CI has increased by 4.4% over 6-7 generations, i.e. by 0.68 percentage points per generation or around 0.14 percentage points per year (taking the average generation interval as five years). This indicates that genetic diversity is being lost, on average, at a rate of 0.14 percentage points per year. At this rate, over the next 100 years, the nine most numerous dog breeds in the UK would, on average, lose 14% of their genetic diversity. Based on present scientific understanding of the rate at which new genetic variation is being continually generated in all living organisms by mutation and other natural phenomena (which can not be taken into account in the above calculations), this predicted loss is not a cause for great concern. Of course, the situation could be very different in the numerically smaller breeds. The results of our present analyses of Australian pedigree files will shed some light on this issue.