Question

1. in chickens, feather color is determined by codominance. when a black chicken (bb) is crossed with a white chicken (ww), the offspring have speckled feathers. if two speckled chickens are crossed, what phenotypic ratio would be expected in their offspring?

a. all speckled
b. 3 speckled: 1 white
c. 1 black: 2 speckled: 1 white
d. 1 black: 1 white

Explanation:

Step1: Determine the genotype of speckled chickens

Since feather color is determined by codominance, when \(BB\) (black) and \(WW\) (white) are crossed, the speckled chickens have genotype \(BW\).

Step2: Set up the Punnett square for \(BW\times BW\)

Gametes	B	W
W	\(BW\) (speckled)	\(WW\) (white)

Step3: Calculate the phenotypic ratio

From the Punnett square, the genotypes and their corresponding phenotypes are: \(BB\) (black), \(BW\) (speckled), \(BW\) (speckled), \(WW\) (white). So the phenotypic ratio is \(1\) black : \(2\) speckled : \(1\) white.

Answer:

C. 1 black: 2 speckled: 1 white