B20: Dog domestication, micro-evolutionary consequences, relatives and interspecies hybrids

Question 1

order
family
genus
species (x5)

Answer 1

Carnivora (order)
Canidae (dog family)
Canis (genus),

most important species:
◦ Canis lupus (wolf)
◦ Canis latrans (coyote)
◦ Canis aureus (jackal)
◦ Canis dingo (Australian wild dog)
◦ Canis familiaris (= Canis lupus f. domestica) (dog, hound, domestic wolf)

Question 2

When were dogs domesticated and where?

Answer 2

one of the first domesticated species.

East Asian origin for the domestic dog, 15,000 years ago.

There is genetic Evidence for an East Asian Origin of Domestic Dogs.
-1500 bp long PCR product from mtDNA.
-Although our data indicates several maternal origins from wolf, 95% of all sequences belonged to three phylogenetic groups universally represented at similar frequencies, suggesting a common origin from a single gene pool for all dog populations.
- A larger genetic variation in East Asia
than in other regions and the pattern of phylogeographic variation suggest an East Asian origin for the domestic dog, 15,000 years ago.

Also:
European origin 18,800 to 32,100 years ago.

Complete Mitochondrial Genomes of Ancient Canids
Suggest a European Origin of Domestic Dogs - 2013
- 16500 bp
- modern and ancient dog (blue) and wolf sequences (orange )
-The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular
dating suggests an onset of domestication there 18,800 to 32,100 years ago.
-These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.

Question 3

number of chromosomes in a dog?

Answer 3

Number of chromosomes is the same in Canis
species group: 2n = 78 (39 pairs).

Question 4

is there chromosome polymorphism across canis species?

Answer 4

No chromosome polymorphism among / across
Canis species.

Question 5

is interspecies hybridisation btw wolf and dog possible?
what new breeds have created?

Answer 5

Interspecies (Wolf × Dog) hybridization is successful!
Offspring are fertile!
New breeds were created by this method (Czech
Wolfhound, Nordic breeds).

Question 6

who was the first DNA sequenced dog?

Answer 6

Tasha the first DNA sequenced boxer (2004)

Question 7

who was the first cloned dog?

Answer 7

Snuppy the first cloned Afghan Greyhound (2005

Question 8

What did mitochondrial DNA research reveal in relation to ancestry of the dog?

Answer 8

Mitochondrion DNA research has revealed: maternal
wolf ancestry, proved also the very early domestication of the dog.
(dog = domestic wolf)

Question 9

What is the consequence of the long evolution of the dog?

Answer 9

• Long evolution: early and new types, highly variable breeds were developed, many new mutations were fixed.
• Consequences: Extreme diversity and variations of breeds (size, body mass; 1-100kg, colours, head shape, genetic defects etc.)
• Socialisation to mankind.
• Feral dogs are not typical and common.

Question 10

give examples of diversity between dog breeds

Answer 10

Extreme Diversity Between Breeds:
◦ Size & body mass (1-100 kg): Toy, small, medium, large breeds.

◦ Coat color & quality: Short-, long-, wire- haired, smooth curly coat etc.

◦ Appearance & conformation:
‣ Head shape: long, brachycephalic, round-headed, square headed, etc.
‣ Ear shape & length: erect, lopped, cropped (illegal)
‣ Tail length & shape (e.g. curled in pugs)
‣ Temperament, senses, instinct
‣ Relationship with humans (companionship, some breeds are better suited to certain
lifestyles)

Question 11

Coat Color Inheritance of the Dog: A

Answer 11

A (agouti signaling protein, ASIP): Ay-, As-, A+-, at-, aa, fawn/ sable (yellow), saddle, wild agouti,
black and tan, recessive black, DNA-test
◦ Polymorphic alleles
◦ Dominance hierarchy: Ay > As > aw or a+ > at> a. colors: DNA -test
‣ Ay- fawn/ sable (yellowish, reddish, darker tips)
‣ As- saddle or blanket
‣ Aw or a+ : wild, wolf color, pale grey, banded
‣ At: black and tan; tan points
‣ Aa: only recessive black (Shetland sheepdog and German Shepard)

Question 12

Coat Color Inheritance of the Dog: B

Answer 12

B (black, tyrosinase related protein, TYRP1 gene, dominant): B-, bb, black brown (chocolate or liver),
DNA test..

Question 13

Coat Color Inheritance of the Dog: C

Answer 13

C (color, thyrosinase): C-, cch-, ce-, cb-, ca, full color, chinchilla, albinos (extreme albino dilution, blue
and pick eyed)

Question 14

Coat Color Inheritance of the Dog: D

Answer 14

D (dense, dilute melanophilin gene, MLPH recessive): D-, dd, diluted colors: grey or blue, cram or
buff. DNA-test

Question 15

Coat Color Inheritance of the Dog: E

Answer 15

E (extension, non-extension, MC1R, melanocortin receptor): Em, Eg, E-, ee, masking, grizzle, full color, yellow or red. DNA-test

Question 16

Coat Color Inheritance of the Dog: G

Answer 16

G (grey): G-, gg, progressive silvering or greying (roan)

Question 17

Coat Color Inheritance of the Dog: K

Answer 17

K (beta-defensin gene, CBD103):
colors: dominant black (KB), brindle (kbr) and agouti fawn (kyky).
DNA test.

Question 18

Coat Color Inheritance of the Dog: M

Answer 18

• M: merle, incomplete dominant, retrotransponzon: M-, mm, MM: subvital, Mm: blue and sable merle, harlequin Dane.
  DNA test

Question 19

Coat Color Inheritance of the Dog: S

Answer 19

S: solid and spotted, microphthalmia- associated transcription factor gene or MITF

S- (solid), si- (irish spotting), sp-(piebald spotting), sw-(extreme piebald spotting),

Question 20

Coat Color Inheritance of the Dog: T

Answer 20

T (ticking): T-, tt, color spotted (Dalmatian)

Question 21

Hair Quality and Texture Inheritance of the Dog: W

Answer 21

• W (wire hair, R-spondin-2 gene, RSPO2):
  ◦ W-; dominant wire hair + beard
  ◦ ww; normal

Question 22

Hair Quality and Texture Inheritance of the Dog: R

Answer 22

R (wavy, curly, keratin-71, KRT71 gene)
◦ R- ; dominant normal
◦ rr – recessive curly coat

Question 23

Hair Quality and Texture Inheritance of the Dog: L-W-R

Answer 23

L-W-R epistatic interactions and combinations:
◦ L- : basset hound (short)
◦ L-, W-: Australian terrier (short wired)
◦ rr-, W-: Airedale terrier (curly wired)
◦ ll: golden retriever (long)
◦ ll, W-: bearded collie (long with beard)
◦ ll, rr: Spanish water spaniel (long and curly)
◦ ll, rr, W- : bichon frise (long, curly, beard)

Question 24

in what breeds is hairlessness dominant and recessive in dogs?

Answer 24

Hairlessness (alopecia, breed standards) in dogs:
◦ Dominant (HR, Mexican Xoloitzcuintli, Peruvian, Inca orchid, Bolivian Khala dogs, American
Hairless terrier)
◦ Recessive (hr) Chinese crested dogs and mandjurian hairless dogs
◦ Hr/ Hr homozygote is lethal → FOX13 gene mutation