What are the drawbacks to lateral gene transfer in microorganisms?

I often joke that it would be supercool if humans could do that too. But seriously, a minute or two of contemplation makes it obvious that, in humans, it would be potentially disastrous.

My question is about microorganisms that practice lateral gene transfer. Do they run the risk of changing or negating the expression of their original genes when adding new ones? It seems to me that random hybridization could result in unforseen complications. (haha, kinda like third party software.)

Of course. But microbes are produced in such gigantic numbers, it would still be worth 99 failures out of every 100 if that 100[sup]th[/sup] one improved fitness. (And humans do do lateral gene transfer–our genome is filled with the debris of foreign DNA.)

Wait, what? Among individuals of our own species? Was this only in earlier forms as we moved along the evolutionary path, or are we still doing it? Where is it theorized that the foreign DNA came from?

More question: Does this lateral transfer include genes like “undulates more when cilia move” and “looks pretty for an amoeba” along with the more mundane traits we tend to discuss? Does a microorganism ever just have its appearance end up wildly different from its cohort? :slight_smile:

Retroviruses. They write themselves into the DNA of organisms to produce copies of themselves, but are sloppy about it so they transfer genes between organisms. Nobody really knows just how much of our DNA comes from transfers between species, since it’s been happening for much longer than our species has existed.

A more specific link.