Question

A test cross of $F_1$ individual produced the following number offspring :

$++/ab=40$ $+b/ab=10$
$a+/ab$ $ab/ab=40$

What is the distance between the genes $A$ and $B$?

• A. $20$ map unit
• B. $10$ map unit
• C. $40$ map unit
• D. $80$ map unit

Answer 1

The correct option is A $20$ map unit

Parental genotype :- $++||ab$ and $ab||ab$

Recombinant genotype:- $+b||ab$ and $a+||ab$

$formula=\frac{TotalRecombinantindividual}{Totalproduction}\times 100$

$=\frac{10+10}{100}\times 100$

$=\frac{20}{100}\times 100$

$=0.2\times 100$

$=20\%$

Distance between $B=20$ map unit

Answer is option $A$.