Topic 57

Question 1

Coat pigment synthesis

Answer 1

Melanocyte-stimulating hormone (MSH) attaches to MCH-R-receptors on melanocytes; Cause increase in tyrosinase enzyme activity; Create pigment synthesis in melaosomes: eu- and phaeomelanin produced

Question 2

What creates various coat colours?

Answer 2

MSH-Receptor gene mutations of alleles at MSHR locus (E locus) create various coat colors.

Question 3

Alleles are

Answer 3

E+, EsuperD, e

Question 4

E+

Answer 4

normal, MSH dependent tyrosinase activity. Different -eu and phaeomelanin production; creare agouti colour

Question 5

EsuperD

Answer 5

continuous tyrosinase activity; MSH binding not necessary; only eumelanin is produced; non agouti colour protein - black

Question 6

e

Answer 6

low tyrosinase activity; red coat colour; only phaeomelanin produced

Question 7

Pigment types

Answer 7

A, B, C, D, E, Indowhite, R

Question 8

A

Answer 8

agouti (yellow/black)

Question 9

B

Answer 9

brown (dun brown in Dexter cattle)

Question 10

C

Answer 10

albino/no pigment

Question 11

D

Answer 11

grey (blue in dog)

Question 12

E

Answer 12

extension (red vs black)

Question 13

Indowhite

Answer 13

palamino

Question 14

R

Answer 14

roan

Question 15

S

Answer 15

spotted

Question 16

Albanism

Answer 16

gene defect causes tyrosinase activity inside melanocyte cells = disrupts melanocyte production causing no pigments to be created. Red eyes e.g. Hungarian Mudi pups