Pekingese and Shih Tzu
What both sides can say, then where they part, then what only one side can say, then what nobody has measured yet. A number without its sample does not appear.
What they share
What cited lifespan means
How long dogs of this breed tend to live, from McMillan 2024 (VetCompass). A population median.
What does genetic diversity mean?
How varied a breed's gene pool is — the share of gene spots where a typical dog of the breed carries two different versions rather than two identical ones.
How to read it: Higher = more diverse. Among well-sampled breeds it ranges roughly 0.22 (least diverse) to 0.33 (most diverse).
Diversity is a strength, not a verdict on any individual dog. Lower diversity means it's worth paying attention to recessive-risk testing — not that a dog is doomed.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
Where they differ
What typical adult weight means
Typical adult weight, in pounds.
What does longevity for its size mean?
How much longer or shorter a breed tends to live than its body size predicts (bigger dogs live shorter on average — this measures the gap from that expectation).
How to read it: Positive = lives longer than its size predicts; negative = shorter. At the extremes, roughly +3 years (longest-lived for its size) down to about -4 years.
A population pattern, not a guarantee for an individual dog.
What genetic neighbors means
Where this breed sits among others in the atlas. Placement, not pedigree.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
One side known
Pekingese: 0% · Shih Tzu: 0.6% (n=85)
What does carrier rate mean?
The share of tested dogs of a breed that carry at least one copy of a specific disease variant.
How to read it: Higher = more common in the breed. 'Carrier' means carrying the variant, not having the disease.
Carrier is NOT the same as affected, especially for recessive variants. Figures come from tested (direct-to-consumer) dogs, which can skew the rate. Worth asking your vet.
What nobody has measured yet
What morrill factors means
A breed lean on this factor in the Darwin's Ark paper. Not a prediction about a dog.