High School

End of Semester Test: Science 8A

Select the correct answer.

A checkered hen mates with a checkered rooster. The genes for the checkered trait are codominant in both parents. What are the chances that their offspring will be checkered?

A. 20 percent
B. 25 percent
C. 50 percent
D. 0 percent
E. 75 percent
F. 100 percent

Answer :

Final answer:

The checkered trait in chickens is governed by codominant alleles, resulting in a 75% probability that their offspring will exhibit the checkered phenotype. This can be determined using a Punnett square, which shows the possible combinations of alleles from both parents. Therefore, the correct answer is 75 percent (option E).


Explanation:

Understanding Inheritance in Checkered Traits


In genetics, when two parents have a certain phenotype (observable traits), the likelihood that their offspring will inherit specific traits can be predicted using a Punnett square. In your scenario, both the checkered hen and the checkered rooster exhibit codominance, which means that both alleles contribute to the offspring's phenotype.


Let’s denote the gene for checkering as C (checkered) and c (non-checkered). If both parents are heterozygous for the checkered trait, their genotypes would be Cc. The possible gametes they can produce are C and c.


Using a Punnett Square


The Punnett square for a cross between two heterozygous parents looks like this:



  • Gametes from the hen: C, c

  • Gametes from the rooster: C, c


Setting up the Punnett square gives you:



  • CC - Both dominant alleles (may appear checkered)

  • Cc - One dominant and one recessive allele (appears checkered)

  • cC - One dominant and one recessive allele (appears checkered)

  • cc - Both recessive alleles (non-checkered)


This results in a distribution: 3 out of 4 outcomes exhibit the checkered phenotype (CC, Cc, cC), meaning that the chances for the offspring to be checkered traits is:



  1. 1 box - CC - checkered

  2. 2 boxes - Cc and cC - both checkered

  3. 1 box - cc - not checkered


Thus, the answer to your question is that there is a 75 percent chance that the offspring will be checkered, so the correct answer is E. 75 percent.


Learn more about codominance in genetics here:

https://brainly.com/question/29794198