Question

Two linked genes $a$ and $b$ show $30$% recombination. The indicidual of a dihybrid cross $++/++$ $ab/ab$ shall produce gametes as

• A. $++80$; $ab$ $20$
• B. $++40$; $ab$ $40$; $+a10$[ $+b10$
• C. $++35$; $ab35$; $+a15$; $+b15$
• D. $++50$; $ab$

Answer 1

The correct option is C $++35$; $ab35$; $+a15$; $+b15$

In the given problem, the recombination is 30%. Hence, it will have 30% crossing over. In this, progeny will be recombinant of both the parents. Hence, there are 15% chances that each progeny will have recombinant genotype, that is +a or +b.

The percentage of linkage = 100 - percentage of recombination = 100 -30 = 70%.

Hence, there are 35% chances that each progeny will be identical to one of their parents, that is either ab or ++.

Thus, the correct answer is option C.