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Originally Posted by bchgirl  Well so say experts with far more knowledge and education regarding genetics than I. You wanna read articles by Carmen Battalia or Jerold Bell to name two.
I do know that inbreeding sets type. Simply because it causes some genes to become homozygous...meaning the same...unlike heterozygous genes which carry differences. So dogs with homozygous genes reproduce themselves because the genes have been "fixed".
There are loads of articles on line regarding inbreeding, genes...some are much easier to understand that others...some I've read several times to understand. lol.
The coefficient of inbreeding in a group of 1000 biewers hovers at around
18%. This is the same COE for standard poodles...some are as high as 25%.
I have seen great strides in structure of the biewers being produced today than several years ago.
I have always been puzzled by the premise of breeding back to a yorkie for health reasons. A)the genetic issues are exactly the same in the two breeds and B)if there are health issues...what benefit do you get when you've bred back to the same dog who health was in question.
As far as the gene pool being considered too small. I own two dogs who do not have any related ancestors until their 5th gen (1 dog)....so there are unrelated dogs out there...
Thanks for saying I'm correct lots of times...  . lol. |
The level of inbreeding is usually measured using a formula called Wright’s Coefficient of Inbreeding.
It calculates the probability that genes may have been inherited from both sides of an individual’s pedigree. It is far
too complex to do by hand over more than two or three generations, but some of the better pedigree software will
calculate coefficient of inbreeding (COI) for you. The usual 3-5 generation pedigree won't give sufficient information
for a useful calculation. The best indicator for calculating inbreeding COI is 10 generations. (Going back 10
generations represents 1024 ancestors)
Modern breeders should know the COI of each of their dogs and determine what the COI will be on planned litters.
Standard Poodles average around 18%. (This is roughly equivalent to all of them being half-brothers and sisters.
Some of the tops stud dogs in the Show World average over 25% or more!) This is unacceptable!!!
Any mammal whose COI is over 6 % is inbred.