In Humans, Straight Thumbs Are Caused by the Dominant Allele

question 48

Multiple Choice

In humans, straight thumbs are caused by the dominant allele T, while individuals who are tt have thumbs that curve backward ("hitchhiker's thumb") . Consider a family in which the father has straight thumbs, and both the mother and their only child have curved thumbs. What is the chance that their next child will have curved thumbs?

• A) 25%
• B) 50%
• C) 75%
• D) 100%

---

Definitions:

Behavioral Geneticists

Scientists who study the role of genetics in behavior, often exploring how genes and environment interact to influence individual differences.

Adopted Children

Children who have been legally taken into a family other than that of their biological parents and raised as members of that family.

Critical Thinking

The process of actively and skillfully conceptualizing, applying, analyzing, synthesizing, and evaluating information to reach an answer or conclusion.

Sex Differences

The biological and physiological distinctions between males and females, often in the context of psychological or behavioral studies.