Đáp án:
Giải thích các bước giải:
$$-$$
$$P: $$ $$AaBbDDEe$$ $$×$$ $$AaBbDDEe$$
Xét riêng từng cặp gen :
$$+)Aa×Aa→$$$$\begin{cases}\dfrac14AA:\dfrac24Aa:\dfrac14aa\\\\\dfrac34A-:\dfrac14aa\end{cases}$$
$$+)Bb×Bb→$$ $$\begin{cases} \dfrac14BB:\dfrac24Bb:\dfrac14bb\\\\\dfrac34B- :\dfrac14bb\end{cases}$$
$$+)DD× DD→1DD→1D-$$
$$+)Ee×Ee→$$ $$\begin{cases} \dfrac14EE:\dfrac24Ee:\dfrac14ee\\\\\dfrac34E- :\dfrac14ee\end{cases}$$
Kiểu gen dị hợp $$2$$ cặp gen là :
$$+)AaBbDDEE=$$2/4xx2/4xx1xx1/4=1/16
$$+)AaBbDDee=$$2/4xx2/4xx1xx1/4=1/16
$$+)AaBBDDEe=$$2/4xx1/4xx1xx2/4=1/16
$$+)AabbDDEe=$$2/4xx1/4xx1xx2/4=1/16
$$+)AABbDDEe=$$1/4xx2/4xx1xx2/4=1/16
$$+)aaBbDDEe=$$1/4xx2/4xx1xx2/4=1/16
-> Tỉ lệ cần tính 1/16xx6=3/8
KH trội về 3 tính trạng:
$$A-B-D-ee=$$3/4xx3/4xx1xx1/4=9/64
$$aaB-D-E-=$$1/4xx3/4xx1xx3/4=9/64
$$A-bbD-E-=$$3/4xx1/4xx1xx3/4=9/64
-> Tỉ lệ cần tính la 9/64+9/64+9/64=27/64
$$\\$$
$$P:AaBbCcDdEe×aaBbccDdee$$
Xét riêng từng cặp gen :
$$Aa×aa→$$1/2A-:1/2aa
$$Bb×Bb→$$3/4B-:1/4$$bb$$
$$Cc×cc→$$1/2C-:1/2cc$$cc$$
$$Dd×Dd→$$3/4D-:1/4$$dd$$
$$Ee×ee→$$1/2E-:1/2ee
Tỉ lệ KH mang $$4$$tính trạng trội là :
+) A-B-C-D-ee = 1/2 × 3/4 × 1/2 × 3/4 × 1/2 = 9/128
+) A-B-C-ddE- = 1/2 × 3/4 × 1/2 × 1/4 × 1/2 = 3/128
+) A-B-c cD-E- = 1/2 × 3/4 × 1/2 × 3/4 × 1/2 = 9/128
+) A-b bC-D-E- = 1/2 × 1/4 × 1/2 × 3/4 × 1/2 = 3/128
+) aaB-C-D-E- = 1/2 × 3/4 × 1/2 × 3/4 × 1/2 = 9/128
Tỉ lệ cần tính là
9/128 + 3/128 + 9/128 + 3/128 + 9/128 = 33/128
