Something Odd I Learned About DNA

Researching the book, I learned something new about DNA modification. Even the simplest bacteria can do it. All this time, we thought it was hard.

There is a soil bacteria called Agrobacterium Tumefaciens, which sounds like a Greek playwright, but which has in fact been performing genetic modification of food for millions of years. What it does it this: it gets up close to its target plant (not so hard when you’re a soil bacteria) and injects a small length of DNA into the cells of the host plant. The cell’s own reproductive system then churns out copy after copy of that DNA, every time the cell divides. That new DNA contains a gene which effectively becomes part of the plant’s genome.

It’s as if this bacteria breaks into the library and scribbles a new recipe in the recipe book. When it’s time for the cell to go to work, it copies the new message along with all the other messages. It doesn’t know that the message has an outside influence.

What’s the message in the new gene? The new message is, ‘Make me more food’. The gene it adds is making sure the plant uses all its energies to produce nutrients that the bacteria likes to consume. Another way of looking at the message might be: ‘Make yourself juicy and succulent so I can eat you’.

Genetic engineering, you see, was happening long before human beings came along and got all moral about it. Evolution was using it so that the strong ate the weak… Or the juicy.