Evolution

In the US there is a big debate as to whether evolution should be taught in schools. The debate never made any sense to me because in India all of us are taught evolution in schools-whatever our religion might be and whatever the religion might say. But in the US the religion does get to dictate what should be taught vis a vis evolution.

I have been following the debate because as a biologist/geneticist/biochemist/whatever, it is pretty obvious to me. Just compare the genome of the chimpanzee with that of the man and you will see that it is 99% similar- something that could not have happened unless we shared the same genome at some point of time. We can go back in time as much as to bacteria and trace the similarity in gene sequences between bacteria and us- a pretty neat evidence that we must have all evolved from the same progenitor at some point or other.

Religion, in that sense, at least to me is a private matter and whether I believe there is a God or not, it does not preclude evolution. In fact I would say there is great many evidences that evolution happened while there is no proof that God exists.

But not to all scientists, obviously. So there have been some my ilk who have been propagating what is known as The Intelligent Design. Basically it says that evolution cannot explain all the diversity we see and therefore, there has to be an intelligent designer i.e. God.

So where am I going with this rambling? We were discussing DNA polymerases in the class. DNA polymerases are proteins that replicate DNA and were first discovered by Arthur Kornberg, for which he got the Nobel Prize. I was explaining how DNA polymerases add new nucleotides to the growing chain of DNA in one direction only because it makes proof reading possible.

A student asked:

"But why cannot we have DNA polymerases doing the same in the other direction? After all if the DNA polymerase did not introduce a wrong base it would have no need for proof reading?"

"Ah, but DNA polymerases are not ideal machines. So they occasionally do make mistakes and have to be rectified. Moreover if DNA polymerases did not make mistakes, there would have been no evolution!"

The class laughed. Of course evolution! Thankfully, none of the students brought up the issue "But God made us all!"