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Why does each bacterial colony on a Petri dish represent a DNA clone?

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DNA extraction and recombinant DNA technology — recombinant DNA The process of DNA extraction is necessary to isolate molecules of DNA from cells or tissues. A series of steps, including the use of protease enzymes to strip proteins from the DNA, are required for isolating pure DNA that is suitable for use in later procedures, such as cloning or sequencing.

In recombinant DNA technology, a bacterial colony on a Petri dish represents a DNA clone because it originates from a single bacterium that has been transformed with a specific recombinant plasmid.1

During the process of transformation, typically only one recombinant DNA molecule enters an individual bacterial cell. As this cell undergoes successive rounds of cell division on a growth medium, it forms a visible colony. Because the recombinant vector is amplified by replication during every round of division, all daughter cells within that colony contain identical copies of the original DNA fragment. Consequently, while the colony is a cell clone, it is also considered a DNA clone because it provides a concentrated population of that specific, replicated DNA sequence.1