Genetics Worked Problem Prototype

Problem Statement

In cucumbers, dull fruit (D) is dominant to glossy fruit (d), and orange fruit (R) is dominant to cream (r) fruit. The genes coding for dull and glossy assort independently from the genes coding for orange and cream. A plant that has dull and orange fruits is crossed to a plant that has dull and cream fruits. The cross produces 3/8 plants with dull and orange fruits, 3/8 plants with dull and cream fruits, 1/8 plants with glossy and orange fruits, and 1/8 plants with glossy and cream fruits. Give the genotypes of the parents and offspring of the cross.

For help with this problem

1. Review Section 3.3 Dihybrid Crosses Reveal the Principles of Independent Assortment

2. Review the steps used in Worked Problem 4 on pg XXX

Choose Steps

Question

Begin by thinking about the steps to take to do this problem. Using the numbers 1-6 place the following steps in order you would perform them to complete the problem.

Identify the Question Being Asked
Determine the phenotypes and proportions expected among the progeny of the cross
Separate the cross into two single locus crosses to asses the inheritance of each trait alone
Put genotypes for each locus together and determine the overall genotypes of the parents and offspring.
Assign the genotypes you can infer from the phenotypes
Write out the information given about the dominance relations of the traits and the allelic symbols for the traits.
Correct.
Incorrect.

Step 1

Question

Identify what you are being asked to do in this question.
You are being asked to find the genotypes of the parents and offspring in the cross of a plant with dull, orange, fruits and a plant with dull, cream fruits.

Step 2

Question

Using single letters, indicate the proper allelic symbol and letter you would use for each trait.

Dull
Glossy
Orange
Cream
Correct.
Incorrect.

Step 3

Write down as much information about the genotype as can be inferred from the phenotype alone. Be sure to answer with Capital letters first, use an underscore symbol (_) to indicate a allele you can not know by phenotype alone and to address each trait in the order it is given (ie: dull first, than orange)

Question 1

dull, orange : x dull, cream :
↓
3/8 dull, orange :
3/8 dull, cream :
1/8 glossy, orange :
1/8 glossy, cream :
Notes: