The American Kennel Club has recognized the familiar blue-and-tan Yorkshire terrier since 1885. The closely related Biewer terrier began as a color variant of the standard Yorkie but is now genetically separate. As of 2014, it is not yet eligible for AKC registration but has its own breed club.
Yorkshire terriers are descendants of dogs bred to catch rodents in Yorkshire coal mines and clothing mills. The original dogs were much larger than present-day Yorkies, which are popular companion dogs. The piebald coloration of the Biewer is due to a recessive gene first observed in 1984. The Biewer terrier's official registry, the Biewer Terrier Club of America, is working toward gaining AKC acceptance for the breed as of 2014.