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Microbiology · Chapter 7

Horizontal Gene Transfer: Three Ways to Share DNA

A dish of bacteria, and one resistance gene already in a few of them. Pick a route and run the dish round by round. Each route moves the gene in its own way, so watch what carries the DNA, what has to die, and how fast the gene spreads. Then try the three blockers and see which route each one stops.

The dish press Run a round

Gene transfer dish

Reading the dish. Green cells carry the resistance gene. Pale cells do not. A dotted edge marks a cell that is competent, meaning it can take up loose DNA. A burst outline marks a cell that broke open and spilled its contents.

Transformationround 0
Round0
Carry the gene3
Cells left0
What carries the DNA—
Contact needed—
Source cell survives—
Spread pattern—
Blockers you can add

Which blocker stops which route

DNase chops up loose DNA, so it only stops the route that leaves DNA out in the open. That one test tells transformation apart from the other two.