If lac+ Hfr bacteria mated with a lac- F- bacteria in an interrupted mating experiment, the F- bacteria will only gain the ability to metabolize lactose if a copy of the lac+ gene recombines with the F- bacteria’s chromosome. Why is recombination into the bacterial chromosome necessary? Recombination is required in order to convert the F- bacteria into Hfr bacteria capable of expressing the genes to metabolize lactose. Although the incoming DNA from the Hfr cell forms a circle, the lac+ locus is not active on a plasmid. Linear DNA is unstable in bacterial cells and unless the lac+ gene is recombined into the bacterial chromosome, it will be destroyed. Recombination is necessary to remove the lac- gene from the bacterial chromosome as this would interfere with the function of the lac+ gene from the Hfr cell. Recombination is required in order to convert the F- bacteria into F+ bacteria capable of expressing the genes to metabolize lactose.

Linear DNA is unstable in bacterial cells and unless the lac+ gene is recombined into the bacterial chromosome, it will be destroyed.

Explanation:

Bacterial recombination is a kind of hereditary recombination in microorganisms described by DNA move starting with one life form called giver then onto the next creature as beneficiary. This cycle happens in three principle ways:  

1. Change, the take-up of exogenous DNA from the general condition.  

2. Transduction, the infection interceded move of DNA between microscopic organisms.  

3. Formation, the exchange of DNA starting with one bacterium then onto the next by means of cell-to-cell contact.

Recombination into the bacterial chromosome necessary because linear DNA is unstable in bacterial cells and unless the lac+ gene is recombined into the bacterial chromosome, it will be destroyed.

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