Most of these random mutations don't help, but every once in a while the system hits upon a slight improvement.

It follows that some process other than random mutation and selection must be involved.

A few more random mutations and the cells could become cancerous.

The problem is usually caused by a random mutation, so parents may not have any family history of the condition.

"It might be just a random mutation," said the doctor, trying to look optimistic.

That is, a second random mutation must occur before a tumor can develop.

Whatever that program does, imagine trying to evolve it by making random mutations in the code.

The evidence is very strong that such changes are indeed brought about by natural selection acting on random mutations.

It is a fact that life evolved by natural selection of random mutations.

My concern is that a random mutation could direct those flies elsewhere.