Question

You are in charge of the national Unicorn breeding program. Unicorns can have either swirled ar solid horns with the swirled (Sw) phenotype being dominant over solid (sw). Their fur can be gold (F), bronze (fb), silver (f) or white (f. with the colour alleles following a dominance series of: Ft > fb>fs > fw

Answer 1

genotype of silver fur, solid horned unicorn - swswfsfw ( since the mother has white fur (fwfw), and fs is dominant over fw)

genotype of white fur, solid horned unicorn - swswfwfw (mother has gold fur (f+fw), and f+ is dominant over fw, so the child has homozygous recessive fwfw)

Cross :

Silver fur, solid horned unicorn * white fur, solid horned unicorn

swswfsfw * swswfwfw

Gametes of swswfsfw :  swfs, swfw

gametes of swswfwfw : swfw

Offspring : swswfsfw ( solid horned /silver fur), swswfwfw (solid horned / white fur)

phenotypic ratio of offspring:

1/2 of the offspring will have silver fur

1/2 of the offspring will have white fur

therefore, the correction option is d - 1/2