Ques 109
Q109. In a dihybrid cross. the two characters are inherited with probability 3 : 1 and 2 : 1 respectively. Find the dihybrid phenotypic ratio
(1) 6 : 3 : 2 : 1
(2) 4 : 2 : 2 : 1
(3) (1 : 2 : 1)2
(4) 9 : 3 : 3 : 1
Dear student
Let us take the two characters as seed shape [Round (R) or Wrinkled (r)] and seed colour [(Yellow (Y) or Green(y)].
The probability of two characters is 3:1 and 2:1 respectively i.e 3 R : 1 r and 2 Y : 1 y.
Then, the phenotypic ratio of the two characters in the dihybrid cross can be determined as:
Let us take the two characters as seed shape [Round (R) or Wrinkled (r)] and seed colour [(Yellow (Y) or Green(y)].
The probability of two characters is 3:1 and 2:1 respectively i.e 3 R : 1 r and 2 Y : 1 y.
Then, the phenotypic ratio of the two characters in the dihybrid cross can be determined as:
(3R + 1r) x (2Y + 1y) = 6RY + 3Ry + 2rY + 1 ry
That is, the 6:3:2:1 phenotypic ratio of round yellow : round green : wrinkled yellow : wrinkled green seeds.
Hence, the correct option is 1.
Regards
That is, the 6:3:2:1 phenotypic ratio of round yellow : round green : wrinkled yellow : wrinkled green seeds.
Hence, the correct option is 1.
Regards