Really interesting subject brought about by the ousting of yet another bad breeder. I still cannot get over that she bragged about breeding merle to merle since even though I don't know much about genetics I do know how to use google.
Although the article is over my head at times I found this & many others just by doing a google search of some of the terms used in recent comments above.
Analysis of Genetic Variation in 28 Dog Breed Populations With 100 Microsatellite Markers