Lines and Families in Shetland Sheepdogs Lines and Families in Shetland Sheepdogs Lines and families are a simplified way of keeping track of relationships among dogs.
Lines consider only the top line of the pedigree, and are traced from sire to son.
While a bitch may be said to be of her sire's line, she never passes that line designation on. Her sons take their line from their sire. Theoretically, dogs of the same line share the same Y chromosome, though given some of the uncertainties in the early breeding records, the results of comparing Y chromosomes within a nominal line might be embarassing. Families work in the same way but trace the bottom line of the pedigree, with descent counted from dam to daughter. Again, a dog may be said to have his mother's family, but he never passes that family designation on.