Solve this:
Mark the odd one ( w.r.t F2 generation of Mendelian dihybrid cross)
(1) Frequency of TtRR genotype = 12.5 %
(2) Frequency of ttrr genotype = 6.25%
(3) Frequency of TTRR genotype = 6.25%
(4) Frequency of ttRr genotype = 25%
Dear Student,
The correct answer is option (4) Frequency of ttRr genotype = 25%
The Mendelian dihybrid cross is represented as follows:
Parents: TTRR X ttrr
Gametes: TR tr
F1 generation: TtRr
F2 generation: TtRr X TtRr
Gametes: TR, Tr, tR, tr TR, Tr, tR, tr
| Gametes | TR | Tr | tR | tr |
| TR | TTRR | TTRr | TtRR | TtRr |
| Tr | TTRr | TTrr | TtRr | Ttrr |
| tR | TtRR | TtRr | ttRR | ttRr |
| tr | TtRr | Ttrr | ttRr | ttrr |
From the Punnett square it is clear that frequency of TtRR genotype = 2/16 X 100 = 12.5%
Frequency of ttrr genotype= 1/16 X 100 = 6.25%
Frequency of TTRR genotype= 1/16 X 100 = 6.25%
Frequency of ttRr genotype = 2/16 X 100 = 12.5%
Regards
