In minks, wild types have black coat. Breeders have developed many pure lines of color variants, for the mink-coat industry. Two such pure lines are blue gray and steel gray. These lines cross, with the following results:
a) The first two crosses show that wild-type is dominant over both platinum and Aleutian. On the other hand, the third cross shows that there is more than one gene with multiple allele, involved in as a ratio of 9:3:3:1 is observed.
Let Platinum be a, Aleutian be b, and the wild type be A/-; B/-.
Cross 1:
Parent:
A/A; B/B X a/a; B/B
Wild type X platinum
F 1 :
A/a; B/B all wild type
F 2 :
Genotypes and phenotypes:
Cross 2:
Parent:
A/A; B/B X A/A; B/B
Wild type X Aleutian
F 1 :
A/a; B/B All wild type
F 2 :
3 A/A; B/b wild type
1 A/A; b/b Aleutian
Cross 3:
Parent:
a/a; B/B X A/A; b/b
Platinum X Aleutian
F 1 :
A/a; B/b all wild type
F 2 :
9 A/-; B/- wild type
3 A/-; b/b Aleutian
3 a/a; B/- Platinum
1 a/a; b/b Sapphire
b) Sapphire X Platinum
Parent:
a/a; b/b X a/a; B/B
F 1 :
a/a; B/b platinum
F 2 :
3 a/a; B/- Platinum
1 a/a; b/b sapphire
Sapphire X Aleutian
Parent:
a/a; b/b X A/A; b/b
F 1:
A/a; b/b Aleutian
F 2 :
3 A/-; b/b Aleutian
1 a/a; b/b Sapphire