Topic 11

Question 1

conformation

Answer 1

correspondance to the model, how something is formed

Question 2

coat color; the 3 pigments

Answer 2

Melanine: black/brown pigment, colours hair, skin and retina

Eumelanine: normally black, found in coat and retina.

Phaeomelanine: Yellow/red pigment, found in coats.

Question 3

coat color; basic process

Answer 3

Basic process: MSH (Melanine stimulating hormone) + receptor gene  tyrosine – melanin pigment synthesis in melanosomes of melanocytes.

Question 4

alleles of basic color

Answer 4

E+ ; wild type, agouti colour. MSH dependent on tyrosinase activity. Different eu- and phaeomelanine production.

EsuperD ; dominant or recessive, black coat colour. Continoustyrosinase activity, butMSH binding not necessary. Eumelanine.

e ; red coat colour. ee homozygote. Low tyrosinase activity, non-functional receptor. Phaeomelanine only.

Question 5

pigment types

Answer 5

A – agouti: Alternation between yellow/black

B – brown

C – albino, no colouration

E – extension

D – grey

Indowhite – palamino

R – roan

Coat colour is registered by a minimum of 6 main loci where multiple alleles andepistatic interactions are common.

Question 6

polledness

Answer 6

polled (PP/Pp) to horned (pp)

Question 7

carped wool gene

Answer 7

Mutation of New Zealand Romney long wool sheep with higher ratio of medullated fibers. Sp; Drydale, Tukidale