Reckon you know your stuff when it comes to co-efficients of inbreeding (COI)? Have a go - or a guess... is it X, Y or Z?
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The answer is here... And if you got it wrong - or even if you got it right and are keen to learn more... there's a fantastic current offer from the Institute of Canine Biology.. a free online course - COI Bootcamp - for breeders.
The answer is, can't say. It takes more than five generations to calculate a meaningful COI.
ReplyDeleteFurthermore, the COI is not the best index possible. What you really want to know is whether inbreeding has concentrated maladaptive genes. Homozygosity in the MHC is -- at least according to modern understanding -- far more important than homozygosity elsewhere. In nature, some highly inbred natural populations, eg., many island species (eg., goats or rats on remote Pacific islands), do fine, while others (eg., the famous Isle Royale wolf populations) are in deep trouble.
The COI is a useful beginning. But we need to be wary of COI (<10), especially for breeds that have a historical bottleneck. Here's hoping we'll have access to better indices.
I got the answer right, but still plan to take the course and refer my dog's breeder to it also. Thanks for the link.
ReplyDeleteOoops I got that wrong, off to boot camp for me. I thought Z. Another cup of cofee and I might see how I got it wrong.
ReplyDeleteI appreciate the COI courses but I think that the Institute could educate breeders more about the benefits of open stud books, outcrosses, and expanded gene pools. I feel like they give in too much to breeders demanding that they continue within their small gene pools, not to "loose type" or whatever. Maybe it's just my impression.
ReplyDeleteYes.
DeleteI think the same goes for the "Canine Genetics and Epidemiology" people. They did do a good job of broadly setting the platform for the Science behind the reasons behind all of these disorders in a joint paper, but then immediately ignored that and started concentrating on the diseases in their own right as though this is going to be the solution.
Every time I get an article "alert" Im shocked all over again at the state of pedigree dogs.
Today's alert is "Genetics and epidemiology of hypothyroidism and symmetrical onychomadesis in the Gordon setter and the English setter"
The breeding fundamentals of pedigree dogs does have to change. That is the solution.
I got it right with no problems. I'll check out the course anyway. I might learn something new or freshen up on something old. However I do agree with those above that said COI isn't everything, it certainly isn't! But it is a start. Then you need to learn your pedigree, what does the dogs in there represent?
ReplyDeleteOoh, sneaky. I thought Z.
ReplyDeleteJennifer, you missed the point. I urge using all generations back to founders for calculation of COI every chance I get (and see here: http://www.instituteofcaninebiology.org/blog/how-many-generations-of-pedigree-data-should-you-use-to-estimate-inbreeding).
ReplyDeleteThis wasn't a question about the best index of homozygosity, or whether DLA homozygosity is more or less important that elsewhere in the genome, and it definitely wasn't about whether 3, 4, or 5 generations of data should be used in the calculation. It was addressing a key point about understanding WHAT the inbreeding coefficient means and HOW it is calculated - the number of times an ancestor appears, and how many generations back - is what determines the probability of homozygosity of alleles that are identical by descent (inherited from the same ancestor).
"...educate breeders more about the benefits of open stud books, outcrosses, and expanded gene pools." - This is precisely what we do, but by educating about the CONSEQUENCES of closed stud books, inbreeding, and small gene pools. You can't understand the benefit of a larger gene pool unless you understand the consequence of having a small one. And we are definitely not "giving in...to breeders demanding..." - We teach about genetic management of populations of animals. The principles are the same whether the stud book is open or closed, whether the gene pool is large or small. If the stud books are open, breeders will still need to practice careful genetic management and understand the consequences of breeding strategies, population size, popular sire, and the many other factors that come into play in determining the distribution and frequency of alleles in a population and how they change over time. The students in our classes don't get a rosy view; usually by the third week they start thinking that their breed is in much worse shape than they thought, and usually that's true. So we teach them WHY, and with that information and some tools to assess genetics, breeders can design breeding strategies that will improve and protect the health of their breed's gene pool.