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AP®︎/College Biology

Course: AP®︎/College Biology > Unit 5

Lesson 3: Non-Mendelian genetics

Non-Mendelian genetics

AP.BIO: IST‑1 (EU), IST‑1.J (LO), IST‑1.J.1 (EK), IST‑1.J.2 (EK), IST‑1.J.4 (EK)

In chickens, the sex-determining chromosomes are called Z and W. Male roosters have two Z chromosomes, and female hens have one Z chromosome and one W chromosome. A gene located on the Z chromosome controls the speed of feather growth in young chicks. The allele for slow-feathering is dominant to the allele for fast-feathering.

During the first few days after hatching, chicks with different feathering speed phenotypes have visually different feather lengths. Chicken breeders often take advantage of this visual difference to quickly determine the sex of newly-hatched chicks. To do this, the breeders have to use parents with specific feathering speed genotypes.

Which of the following crosses will result in chicks whose sex can be determined based on their feathering speed phenotype?

(Choice A)
a cross between a slow-feathering female and a fast-feathering male
(Choice B)
a cross between a slow-feathering female and a true-breeding, slow-feathering male
(Choice C)
a cross between a fast-feathering female and a true-breeding, slow-feathering male
(Choice D)
a cross between a fast-feathering female and a fast-feathering male

Stuck?

AP®︎/College Biology

Course: AP®︎/College Biology > Unit 5

Problem