I’m a computer programmer so I actually found it quite interesting since the author made an analogy between computer and human viruses

you can learn a lot about flu virus, it’s program code, how it works and what can be done to make it more lethal or benign

here’s the link http://www.bunniestudios.com/blog/?p=353

one bacteria lead to many and he made 12 different populations that he kept going for 20 years

but then, at about 31 thousand 500 generations of bacteria later, he noticed Escherichia gained the ability to metabolise citrate

the other populations didn’t develop this

now, being careful, Lenski has an archive of every 500 generations stored, so he could replay the process and see if the later generations would develop the same ability (mutation)

the result was, only the original population developed the same mutation when replayed

read more about it here