The mechanism that causes a gene to move from one linkage group to another is called 

(1) inversion

(2) duplication

(3) translocation

(4) crossing-over

Which of the following shows linkage group in coupling phase?

(1)  $\underline{A B}$
$\overline{a b}$

(2)  $\underline{A b }$
$\overline{a B}$

(3)  $\underline{A b}$
$\overline{a b}$

(4)  $\underline{a B}$
$\overline{a b}$

The number of linkage group(s) present in Escherichia coli is 

(1) One

(2) two

(3) four

(4) seven

The movement of a gene from one linkage group to another is called: