I specialize in pure bread yorkshire Terriers. All my dogs are AKC. I no longer register my litters. This weeds out the breeders. DNA is better than AKC. When I have Merle colors the parents are a mix of yorkshire Terrier and /Biewer Terrier. I use DNA embark. There are no bad gene hereditary variances in the generic line. I'm pround . I'm still educating myself.