• Question: is there anyone alive who doesn't have mutations? if so why?

    Asked by lily4 on 13 Jan 2014.
    • Photo: Simon Butt

      Simon Butt answered on 13 Jan 2014:

      What a fantastic questions and my immediate answer would be no (although I’m wondering if there is a way to make it a possibility…).

      Naturally occurring mutations arise spontaneously (so potentially from the moment you are a fertilized egg), after replication of the DNA (during cell division – so while you are developing as an embryo), or during DNA repair. Throughout our development, cells in our body are constantly trying to restore the DNA back to its original state but it is quite the battle! But then again not all mutations are negative and some in the end can be beneficial and give us an evolutionary advantage so it is not all ‘bad’ news. Indeed what is a ‘non-mutant’? As I suppose we could argue that we are all the products of numerous beneficial mutations over time – both in our ancestors and during our own lives.

      To not have mutations you would need someone or something never exposed to mutagens with perfect cellular machinery operating at 100% efficiency, across all the cells in their body for their entire lives! That would be amazing.

    • Photo: Vicky Forster

      Vicky Forster answered on 13 Jan 2014:

      Good question, and I agree with Simon – definitely not. It is generally believed that each time every cell in your body divides, it has around 100 mutations in it’s DNA – however almost all of the time, these are repaired by proteins which carry out a process called DNA repair. Sometimes though, these DNA repair mechanisms go wrong, or simply miss a mutation, and mutations remain in the DNA. Most of the time, this won’t cause a problem, but if the mutation is in an important bit of DNA called a gene, which is important in that type of cell – diseases such as cancer can happen. Most of us will have a lot of mutations in our DNA, that don’t cause any diseases or problems. Viruses for example can cause mutations in DNA, because they paste their DNA into that of our cells so that our cells copy it and allow the viruses to replicate.

    • Photo: Amanda Carr

      Amanda Carr answered on 13 Jan 2014:

      Great question and I agree with Simon and Vicky, I don’t think there is anyone alive who doesn’t have a mutation.

      A mutation is a difference in the sequence of the DNA. When we look to see whether the DNA in a particular person has a mutation we compare their DNA sequence to a reference produced by the Human Genome Project. This reference sequence was created from a number of anonymous donors. Their DNA was broken up into smaller more manageable fragments, sequenced and then pieced together, so the reference is actually a hypothetical genome rather than the sequence of a “normal” person.

      If you compare your DNA to the Human Genome Sequence about 1 in every 1000 bases would be different, and classed as a mutation. The same is true for me and the person sitting next to you. Even identical twins, who share “the same DNA” have differences between their DNA.

      As humans we are all around 99.9% similar when we look at our DNA, but these changes, or mutations, help to make us all individual.