Mailbag: Mutations and perfect people

A friend of mine and I were discussing evolution, my friend is a Christian and told me that the human mutation rate is 1 in ten billion cell duplications, and with this rate you can track back to the 'genetically perfect human' around 6000 years ago, which is apparently when God created man. I'm quite sceptical of this, considering i have learnt about mutations in science and biology this year at school, so i was wondering whether you could tell me what the rate is and whether it is even possible for there to have been a 'genetically perfect human', after all when it comes to genetics what is classified as perfect? If you could answer this question it would be greatly apprectiated.

I appreciate your question. To really explore the topic, I suggest the free materials from Nature education. For example, this article about mutations has links to many other related topics.

The short answer is that human DNA has mutated around 2/100000000 per generation per base pair. The average two copies of a gene in people today differ by 1/1000, making their common ancestor around 50000 generations (1 million years) ago. No person is genetically perfect – even discounting new mutations, some of our genes work only in combination with others. Natural selection has eliminated many deleterious mutations but thousands of them remain and have always existed.