What are the genotypes of the parents if male offspring resulted in a 50% cock-feathered and 50% hen-feathered ratio?

What are the genotypes of the parents if male offspring resulted in a 50% cock-feathered and 50% hen-feathered ratio?

• A. HhZZ male; hhZW female
• B. HHZZ male; hhZW female
• C. HhZZ male; HhZW female
• D. hhZZ male; HhZW female

Answer: (A)

To derive the genotypes of the parents based on the offspring's phenotypic ratio, we need to consider the aspect of sex-linked inheritance, specifically with feathering in chickens, where cock-feathered (laced, or spangled) and hen-feathered traits are importantly visible. In this scenario, the offspring exhibit a 50% ratio of cock-feathered to hen-feathered males. This suggests that the determining genes for feathering are located on the Z chromosome, where males are heterogametic (XY) and females are homogametic (XX), allowing for sex-linked trait inheritance patterns. The presence of two distinct phenotypes in equal proportions among male offspring implies that the genetic makeup must include one allele that leads to cock-feathering and another that leads to hen-feathering. In the context of the provided choices, focusing on choice A provides a valid pairing: 1. The male parent is HhZZ. This indicates he carries one allele (H) that contributes to cock-feathering and is homozygous for the Z chromosome. This male will pass on the Z chromosome with a 50% likelihood of providing the cock-feathering trait (H). 2. The female parent is hh

To derive the genotypes of the parents based on the offspring's phenotypic ratio, we need to consider the aspect of sex-linked inheritance, specifically with feathering in chickens, where cock-feathered (laced, or spangled) and hen-feathered traits are importantly visible.

In this scenario, the offspring exhibit a 50% ratio of cock-feathered to hen-feathered males. This suggests that the determining genes for feathering are located on the Z chromosome, where males are heterogametic (XY) and females are homogametic (XX), allowing for sex-linked trait inheritance patterns.

The presence of two distinct phenotypes in equal proportions among male offspring implies that the genetic makeup must include one allele that leads to cock-feathering and another that leads to hen-feathering. In the context of the provided choices, focusing on choice A provides a valid pairing:

1. The male parent is HhZZ. This indicates he carries one allele (H) that contributes to cock-feathering and is homozygous for the Z chromosome. This male will pass on the Z chromosome with a 50% likelihood of providing the cock-feathering trait (H).

2. The female parent is hh