Answer :
Answer:
The term that fills in the blank is **"horizontal" gene transfer.**
Explanation:
Horizontal gene transfer refers to the transfer of genetic material between different organisms, often of the same generation.
In the context of the question, when two bacterial strains (His-/Trp- and Leu-/Thr-) are mixed and plated on minimal media, any colonies that form are likely the result of one strain acquiring genes from the other strain horizontally.
This transfer allows the recipient strain to gain the ability to synthesize histidine (His), tryptophan (Trp), leucine (Leu), and threonine (Thr), which were initially lacking. Horizontal gene transfer mechanisms include transformation, transduction, and conjugation.
The occurrence of colonies on minimal media indicates successful acquisition of the necessary genes, providing a selective advantage for bacterial survival and growth in that environment.
Final answer:
The gene transfer described is called bacterial conjugation, a form of horizontal gene transfer.
Explanation:
The process described, where two bacterial strains acquire genes from each other, is called bacterial conjugation. Bacterial conjugation is a form of horizontal gene transfer (HGT), which is the introduction of genetic material from one species to another by mechanisms other than vertical transmission. In this case, the bacteria transfer genes that are required for growth in certain conditions. Bacterial conjugation involves the use of a structure called a pilus to transfer DNA between cells.
