Campbell Biology (10th Edition)

Published by Pearson
ISBN 10: 0321775651
ISBN 13: 978-0-32177-565-8

Chapter 15 - 15.2 - Concept Check: 2


50% if the second child is a boy, 0% if the second child is a girl. Overall, 25% chance.

Work Step by Step

Here, make a Punnett square for a monohybrid cross. Since the trait is sex-linked and Tim lacks it, he must be D- (one allele for normal dystrophin, one non-allele on his Y chromosome), and Rhoda must be Dd. Her d allele passed to the first child born. Girls will always get Tim's D allele and not have the disease while boys have a 50% chance of getting the d allele and a 50% chance of getting the D allele.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.