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Câu hỏi: Nếu các gen liên hết hoàn toàn, một gen quy định một tính trạng, gen trội là trội hoàn toàn thì phép lai nào sau đây cho tỉ lệ kiểu hình 3 :1
A. $\dfrac{Ab}{aB}\times \dfrac{Ab}{aB}$
B. $\dfrac{AB}{ab}\times \dfrac{AB}{ab}$
C. $\dfrac{AB}{ab}\times \dfrac{Ab}{aB}$
D. $\dfrac{AB}{ab}\times \dfrac{ab}{ab}$
A. $\dfrac{Ab}{aB}\times \dfrac{Ab}{aB}$
B. $\dfrac{AB}{ab}\times \dfrac{AB}{ab}$
C. $\dfrac{AB}{ab}\times \dfrac{Ab}{aB}$
D. $\dfrac{AB}{ab}\times \dfrac{ab}{ab}$
A. $\dfrac{Ab}{aB}\times \dfrac{Ab}{aB}\to 1\dfrac{Ab}{Ab}:2\dfrac{Ab}{aB}:1\dfrac{aB}{aB}\to KH:1:2:1$
B. $\dfrac{AB}{ab}\times \dfrac{AB}{ab}\to 1\dfrac{AB}{AB}:2\dfrac{AB}{ab}:1\dfrac{ab}{ab}\to KH:3:1$
C. $\dfrac{AB}{ab}\times \dfrac{Ab}{aB}\to 1\dfrac{AB}{Ab}:1\dfrac{AB}{aB}:1\dfrac{Ab}{ab}:1\dfrac{aB}{ab}\to KH:1:2:1$
D. $\dfrac{AB}{ab}\times \dfrac{ab}{ab}\to 1\dfrac{AB}{ab}:1\dfrac{ab}{ab}\to KH:1:1$
B. $\dfrac{AB}{ab}\times \dfrac{AB}{ab}\to 1\dfrac{AB}{AB}:2\dfrac{AB}{ab}:1\dfrac{ab}{ab}\to KH:3:1$
C. $\dfrac{AB}{ab}\times \dfrac{Ab}{aB}\to 1\dfrac{AB}{Ab}:1\dfrac{AB}{aB}:1\dfrac{Ab}{ab}:1\dfrac{aB}{ab}\to KH:1:2:1$
D. $\dfrac{AB}{ab}\times \dfrac{ab}{ab}\to 1\dfrac{AB}{ab}:1\dfrac{ab}{ab}\to KH:1:1$
Đáp án B.