This is Guillermo Davis from Lima, Peru. My question is: Is evolution, natural selection still working in the human race in the present day? Could you provide examples of positive beneficial mutations in humans?
Chris - I reckon the answer is probably yes. What do we think?
Kat - Yes. Evolution, natural selection is basically the response of organisms to changes in their environment. Our environment is changing. We are adapting. We've grown in size a lot due to better nutrition over the past 100,000 years.
Chris - Yes, I think I'd probably add to that and say there are good examples of things like sickle cell anaemia where people have evolved this trait which makes your haemoglobin a funny shape which means it's not so good if you have two copies of that gene. If you have one copy you can't catch malaria. That's a good example of a mutation that benefits you in Europe. Lactose intolerance is absent but it's present in other populations in the world. We have evolved a gene in Europe which enables us to digest lactose, a major sugar in milk because people began to farm cows. There's another mutation that makes us healthier.
Kat - They say the genes for very fair hair and red headed are dying out because of inbreeding. We are evolving that way.
Chris - And also resistance to HIV, there's CCR5-delta-32. This is an alternative form of a gene in the immune system which happens to give you, if you're a carrier of that, resistance to HIV infection. This has only really surfaced as important since HIV came along. There's a couple of us gaining a new mutation.
Dave - Although I guess in Western countries where pretty much everybody survives the only real survival of the fittest is to do with how many children you have. The direction in which the western population is evolving is towards the people who have the most children.
Kat - It's the breeders!