Question

Palomino horses have a golden yellow coat, chestnut horses have a brown coat, and cremello horses have a coat that is almost white. A series of crosses between the three different types of horses produced the following offspring:

Cross Offspring
palomino x palomino 13 palomino, 6 chestnut, 5 cremello
chestnut x chestnut 16 chestnut
cremello x cremello 13 cremello
palomino x chestnut 8 palomino, 9 chestnut
palomino x cremello 11 palomino, 11 cremello
chestnut x cremello 23 palomino
a. Explain the inheritance of the palomino, chestnut, and cremello phenotypes in horses.
b. Assign symbols for the alleles that determine these phenotypes.

Answer 1

Palomino nuts will be heterozygous this is because when two palomino are crossed, the F1 phenotypic ratio is 2:1:1 this means its alleles are incompletely dominant. It shows the palomino resulted from the cross of chestnut and cremello and due to the incomplete dominance it resulted to an intermediate phenotype of golden yellow coat

Whereas the cremello and the Chestnut are have homozygous traits.

Putting into consideration that chestnut and cremello have homozygous traits. We may Assign their alleles as;

Chestnut =A

Cremello= B

Therefore, Palomino will be AB since it is heterozygous