Dog Genetics

Question 1

diploid number (how many chromosomes?)

Answer 1

78
38 pairs, 1 pair of sex chromosomes

Question 2

incomplete dominance

Answer 2

heterozygote in-between two homozygotes
(ex. cross wire haired and smooth haired, get something in between)

Question 3

dog homozygous lethal trait

Answer 3

hairlessness

Question 4

ticking

Answer 4

spots of color in white areas

Question 5

merle associated problems

Answer 5

often blind, eyes may be small/malformed
often deaf
sterile if they survive
pups may die or be euthanized
homozygous semi-lethal
cross merle with non merle to get surviving puppies

Question 6

pleiotropy

Answer 6

one gene affects multiple traits
ex. merle gene; affects coloring, eye and ear formation

Question 7

dalmatian genetic problems

Answer 7

deafness is common
produce uric acid, causes bladder stones

Question 8

hip dysplasia

Answer 8

genetic problem in many breeds
hip joint breaks down
can be diagnosed by x-ray
can ask breeder if parents are certified to not have hip dysplasia, selects for dogs with better hips

Question 9

breeder induced problems

Answer 9

occur due to poor selection from breeders

Question 10

collie eye anomaly

Answer 10

selection for long narrow muzzle has changed shape of skull
causes vision problems, detached retina, optic nerve pressure

Question 11

bulldog breeder-induced problems

Answer 11

short muzzle causes respiratory problems, tear duct drainage issues
difficult to birth due to head and shoulders, have to be born by c-section

Question 12

dachsund breeder-induced problems

Answer 12

back problems from selection for long body

Question 13

boxer breeder induced problems

Answer 13

back problems from selection for tight muscled look

Question 14

sharpei breeder induced problems

Answer 14

selection for wrinkly skin

Question 15

inbreeding

Answer 15

increases homozygosity
increases predictability and incidence of deleterious (bad) recessive traits

Question 16

how to breed a dalmatian that doesn’t produce uric acid

Answer 16

cross dalmatian with pointer
generation 1: heterozygous, likely none will produce uric acid
backcross to a dalmatian (50/50)
eliminate any that produce uric acid
backcross again to a dalmatian (75/25)
repeat, selecting for dalmatian type and color until almost 100%