Kody, a boy, and Shakira, a girl, are brother and sister. They both inherit the same recessive allele for trait T on their X chromosome from their mother. What is the relative likelihood of Kody and Shakira expressing trait T?

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Quizplus · Accepted Answer

Kody has only one X chromosome (XY), so if he inherits a recessive allele for trait T from his mother, he will express it because he lacks a second X chromosome that could potentially carry a dominant allele to mask the recessive one. Shakira, on the other hand, has two X chromosomes (XX), so she would need to inherit the recessive allele for trait T from both parents to express the trait. Therefore, Kody is more likely to express trait T than Shakira.

Kody, a Boy, and Shakira, a Girl, Are Brother and Sister