Using the lytic bacteriophage P22 you perform a three-factor cross in Salmonella typhimurium. The phage is initially grown on an Arg+ Leu+ His+ strain of S. typhimurium. The progeny phages are then infected into a recipient bacterium which is Arg- Leu- His-. You select 1000 Arg+ recipients and test them on several selective media by replica plating with the following results:

Class 1 = Arg+ Leu- His- = 575

Class 2 = Arg+ Leu- His+ = 365

Class 3 = Arg+ Leu+ His+ = 140

Class 4 = Arg+ Leu+ His- = 1

8.  What is the complete name given to gene transfer of this type (two words)?