Since some very strange genetic health problems started surfacing
recently, I was determined to research the pedigrees of the effected dogs in hopes of some
answers. My kitchen table soon proved to be much too small to contain the volumes of paper
I was using, trying to go back only 9 generations! Since all of the Shilohs are already
heavily "linebred" and some breedings now taking place are intensifying this
problem even more, I wanted to determine the coefficients, since such breedings increase
the occurrence of deleterious recessive traits. I had spent several months discussing our
lines with an expert geneticist, and he recommended a program that Cornell University, as
well as many others, have been using. Since I was not getting very far with my kitchen
table & calculator, I figured I would look into his suggestion. It has taken me awhile
to get "familiar" with using only a small part of the program, but the data that
I have been seeing is absolutely amazing!
We are all aware of the "dark side of inbreeding," and I even
mentioned some of the problems that could arise from incomplete data on "past
generations" in my other article. Mr. Fred Lanting states that "In livestock
breeding, 6.25% is often used as an upper limit for an acceptable level of inbreeding in a
population." He has also advocated that clubs maintain a geneticist "to keep
track of the kinship or inbreeding coefficients." In order to prevent defective
homozygotes (an organism that possesses identical alleles at a given gene locus) it is
imperative to determine the inbreeding coefficient (a number used to qualify the
PROBABILITY that an organism will have identical alleles from the same ancestral source).
The program I am using even provided the Homozygous %, up to 30 generations! In a
30-generation pedigree the maximum possible ancestors is 2,147,483,646. !! So far we have
close to 45,000 of these programmed in, with more to be added shortly.
1/99 Update; I have completed my preliminary evaluations
of the popularly used Shiloh Shepherd genepool. When randomly selecting reports from a
pile of over 100, the following Relationship Coefficient % had been calculated as 49.267,
36.269, 52.026, 34.598, 28.167, 63.526, 45.248. Upon closer examination I discovered that
most ranged in the mid-high 30's. Only 4 were found that averaged in the low 20's, and
over 1/3rd ran well over 40%. The lowest RC found was 14.729 (from a NB breeding) the
highest found was 68.329.