Science - USA (2022-04-29)

(fig.S13C).Mostquestions(72%)andfac-
tors (63%) are correlated with age [false dis-
covery rate (FDR)pvalue (pFDR) < 0.05] (figs.
S15 and S16). Older dogs score nearly as com-
posed in their arousal level (factor 2) as the

most composed breed (Great Pyrenees), and

puppies are far more toy-directed in their

motor patterns (factor 3) than one of the

most toy-directed breeds (German shepherd

dog) (Fig. 4, F and G).

Testing breed stereotypes

PPSs aligned, to a limited degree, with be-

havioral stereotypes described in the breed

standards (data S12). The American Kennel Club

(AKC) describes each breed with a three-word

Morrillet al.,Science 376 , eabk0639 (2022) 29 April 2022 6 of 15

Fig. 4. Breed and age
(and not size) have
subtle effects on the
behavior traits surveyed.
(A) LD-corrected SNP-
based heritability is much
higher for physical traits,
and somewhat higher
for motor patterns,
compared with other
behavioral traits
(significance measured
using Student’sttest;
Benjamini-Hochberg
(BH)–adjustedpvalue is
shown). Shaded regions
indicate the probability
density. (BandC) ANOVA
in confirmed purebred
dogs shows that (B)
the effect size of breed
exceeds 15% for 6/7
physical traits and some
behavioral questions
(labeled bars) and that
(C) for factors, breed
explains more variation in
scores than age and sex,
and size has no significant
effects. In (C), asterisks
indicate statistical signifi-
cance (BH-adjustedp<
0.05). (DandE) Permu-
tations comparing breeds
to randomly sampled dogs
show that (D) many
breeds are significantly
differentiated on physical
traits but that differentia-
tion is much rarer for
behavioral traits, including
intrinsic motor patterns
and (E) the eight behav-
ioral factors. The selection
of the most popular
and/or most differentiated
breeds is shown, with
full results in fig. S12.
Breeds in italics are
represented by fewer
than 50 individuals and
skew toward more
extremez-scores (gray
background; difference in
mean score = 0.29;pt-test=2×10−^71 ). (F) The effect of age, compared with the effect of breed, in the ANOVA shows that age explains nearly as
much variance as breed for factor 2. (G) The PPS for arousal level and toy-directed motor patterns are significantly correlated with age, whereas biddability is more
breed driven. Asterisks indicate significant results.

0510

aroused

composed

age (years)

2 R=0.98*

siberian

husky*

0510

toy−directed

not toy−directed

age (years)

3 R=0.97* 4 R=−0.69

0510

biddable

independent

age (years)

z (permutations)

effect of breed

effect of age

0.0

0.1

0.0 0.1 0.2

−3

0

3

#1 Human sociability

less sociable highly sociable

#8 Proximity seeking

affectionate aloof

#2 Arousal level

aroused composed

#3 Toy-directed motor patterns

toy−directed not toy−directed

#4 Biddability

biddable independent

#5 Agonistic threshold

assertive diffident

#7 Environmental engagement

engaged not engaged

heritability

1 2 3 4 5 6 7 8

#6 Dog sociability

less sociable highly sociable

permutation z-score

0% 100%−4 −2 0 2 4

heritability

missing

candidate purebred dogs N=25

heritability

confirmed

purebred

N=50

#17: Howlsnever always

#54: Retrievesagree disagree

#59: Pointsagree disagree

#121: Sizetiny giant

#125: Ear shapedropped pricked

#127: Fur lengthshort long

Physical traits

Motor pattern related

Factors

pcorr<0.05

effect size (ges)

12345678

factor

0.0

0.2

0.0

0.2age

0.0

0.2size

0.0

0.2breed

sex

0.0

0.2

0.4

0.6

0.8

ef

fect size of breed (ges)Howls

Retrieves objects

Points

Easy to train

Curly tail

Size

White fur

Ear shape

Fur length

Fur texture

Avoids getting wet

Rests frog style

question number

B

motor pattern

other behavior

physical trait

physical trait related

C

D

E

FG

heritability (h

2 SNP

sum)

0.35

0.0013

0.041

0.00063

physical

trait

physical

trait

related

motor

pattern

factor other

behavior

0%

20%

40%

60%

80%

100%

A

border

collie*

great

pyrenees*

beagle*

great

pyrenees*

greyhound*

great

pyrenees*

german

shepherd

german shepherdgolden retrieverlabrador retrieveramerican cocker spanielamerican pit bull terrieram staffordshire terrieraustralian cattle dogaustralian shepherdbasset houndbeaglebelgian malinoisbernese mountain dogborder collieboston terrierboxercatahoula leopard dogcav king charles spanielchihuahuadachshundgreat pyreneesgreyhoundminiature pinscherpapillonshiba inusiberian huskyvizslaw highland white terrierwhippetyorkshire terrier

australian shepherdborder colliegerman shepherdgolden retrieverlabrador retrieveralaskan malamuteamerican cocker spanielamerican pit bull terrieram staffordshire terrieraustralian cattle dogaustralian shepherdbasset houndbeaglebelgian malinoisbernese mountain dogborder collieboston terrierboxerbrittanycatahoula leopard dogcav king charles spanielchihuahuaenglish bulldogenglish springer spanielgerm shorthaired pointerlhasa apsominiature pinscherpapillonsiberian huskytreeing walker coonhoundvizslaw highland white terrierwhippetyorkshire terrier

yorkshire

terrier

border

collie

dachshundgerman shepherd doggolden retrievergreat pyreneesgreyhoundlabrador retrievershiba inu

alaskan malamute brittany english bulldoggerman shepherd doggolden retrieverlabrador retrieverlhasa apso

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