The evaluation of sire and dam lines is important because of its relationship to genetic diversity in the breed. The number of distinct sire and dam lines is a reflection of the breadth of the foundation for the breed; each line traces back to a unique sire or dam founder.
It is NOT the case that different sire & dam lines in the breed today are unrelated, however. At this point in breed history, the representatives of different sire and dam lines are related to one another through a web of ancestral connections. The web of relationships grows more tangled with each generation removed from the original founding dogs.
Illustration:
- blue boxes = some sire line founders
- green boxes = a few key descendants of various sire lines
- yellow boxes = well known representatives of different sire lines
The arrows connecting the boxes show which dogs contribute to the pedigree of each descendant. The red arrows are sire lines, the other arrows are connections that can be found from looking at other lines in the pedigree.
Example: Sparkplug is from the Tyrone Bill sire line. Other sire founders in his pedigree include Emanuel’s Butch, Winkler’s Hiawatha, Sonny, Stodghill dog, Maple Hill Laddie, Old Sport, Shep B, King S and Old Black Joe. All three of the “green” key descendants (Anderson’s Bow, Sam Odie and Wilsons King) are also present in Sparkplug’s pedigree.
So, if the different sire and dam lines include dogs that are genetically related, what is the point of distinguishing them? The sire and dam lines present today reflect the dogs currently being selected for breeding. Knowing the most remote ancestor on the sire/dam line is interesting but knowing the prevalence of the line within the current breeding population, the number of branches in the line, and how far back in the pedigree (generations) those branch points occur, allows us to track the pattern of growth in the breed. A healthy breed will maintain a wide array of sire and dam lines, with new branches added at each generation as multiple descendants are used to maintain the breed’s genetic foundation; a breed undergoing heavy selection and genetic bottlenecks will have a dwindling number of lines and few branches.
Researching Your Dog’s Pedigree
- When you look at your dog’s pedigree, what do you see on the top (sire) line?
- What is the bottom (dam) line?
- Which other founder lines do you find interwoven among the ancestors behind your dog?
- Do any dogs appear more than once in recent generations in the pedigree?
You can find charts showing data on the prevalence of various sire and dam lines from our most recent review of ESCR data (2019 – 2021 for sires, 2019 – 2022 for dams) at these links:
Sire Line Summary Chart
Dam Line Summary Chart
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