A rooster with gray feathers and a hen of the same phenotype produce 15 gray, 6 black, and 8 white chicks. What is the simplest explanation for the inheritance of these colors in chickens? What phenotypes would you expect in the offspring of a cross between a gray rooster and a black hen?

Short Answer

Expert verified

When a rooster with gray feathers crosses with a hen having the same colored feathers, the offspring has three types of phenotypes: gray, black, and white. It shows incomplete dominance because black feathers are not completely dominant over white feathers.

When a gray rooster is crossed with a black hen, the offspring will be gray and black in equal amounts.

Step by step solution

01

Inheritance

Inheritance is the process by which genes are transferred to the offspring from their parents. These genes, when combined in different manners, make an organism unique in its characters.

So inheritance decides the characteristics of all living organisms. A single gene controls some characters, and many are controlled by interactions of two or more genes.

02

Step 2: Incomplete dominance

Incomplete dominance is a modified form of the principle of the dominance of Mendel. It is the phenomenon or the gene interaction in which dominant and recessive alleles both express and give their phenotypic effects, and an intermediate type of heterozygote is obtained.

03

Step 3: Explanation of incomplete dominance

In the given case, black is not completely dominant and cannot mask the effect of white, so gray-colored roosters are present that produce three types of phenotypes. If there was complete dominance, phenotypes would be black and white.

However, the presence of gray-colored heterozygote explains incomplete dominance. The phenotypic ratio in incomplete dominance is 1:2:1 (6 black,15 gray, and 8 white).

According to the Punnet square method, the phenotype of offspring in a cross between a gray rooster and a black hen will be gray and black.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The continuity of life is based on heritable information in the form of DNA. In a short essay (100-150 word), explain how the passage of genes from parents to offspring, in the form of particular alleles, ensures perpetuation of parental traits in offspring and, at the same time, genetic variation among offspring. Use genetic terms in your explanation.

In 1981, a stray black cat with unusual rounded, curled-black ears was adopted by a family in California. Hundreds of descendants of the cat have since been born, and cat fanciers hope to develop a true–breeding variety. How would you determine whether the curl allele is dominant or recessive? How would you obtain true-breeding curl cats? How could you be sure they are true-breeding?

The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individuals, indicated hereby the colored circles and squares, are unable to metabolize a substance called alkapton, which colors the urine and stains body tissues. Does alkaptonuria appear to be caused by a dominant allele or a recessive allele? Fill in the genotypes of the individuals whose genotypes can be deduced. What genotypes are possible for each of the other individuals?

In table 14.1, note the phenotypic ratio of the dominant to recessive traits in the F2 generation for the monohybrid cross involving flower color. Then determine the phenotypic ratio for the offspring of the second generation couple in Figure 14.15b. What accounts for the difference in the two ratios?

Hemochromatosis is an inherited disease caused by a recessive allele. If a woman and her husband, who are both carriers, have three children, what is the probability of each of the following?

(a) All three children are of normal phenotype.

(b) One or more of the three children have the disease.

(c) All three children have the disease.

(d) At least one child is phenotypically normal.

(Note: It will help to remember that the probabilities of all possible outcomes always add up to 1.)

See all solutions

Recommended explanations on Biology Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free