From what I understand of genetics, the qualities that our breed values in ears are from recessive genes. Qualities like small, high-set, and narrow ear leathers which give the yorkie a proper ear. Because these are recessive if the dog shows these traits it is homozygous for these traits. If you breed to another dog that is homozygous for these traits all the pups should have lovely ears. If you breed a dog with bad ears to one with good ears your taking your chances. The bad eared dog may be either homo or heterozygous for the trait and you'll end up with pups that have bad ears if homozygous. If heterozygous you'll end up with 2 out of 4 pups with bad ears (theoredically). It's easier to breed a recessive trait in or out than a dominant one.
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Tami |