• Question: Can all pretty serios diseases be somehow linked to our DNA?

    Asked by anon-256604 on 8 Jun 2020.
    • Photo: Alex Holmes

      Alex Holmes answered on 8 Jun 2020:

      Hi Polina!

      I’m going to say “no” as my answer to the question you asked. Lots of diseases are caused by genetics, like cystic fibrosis, some cancers, muscular dystrophies and things like that. However, there are a lot of serious diseases that just happen, because someone caught a particular virus or bacteria or because some skin cells were damaged by UV from the sun or because a parasite was in some food.

      I guess you could argue though, that if we had the right genes we’d be able to fight these diseases off though. Like if there was a gene to produce penicillin (like some microbes have) then maybe we wouldn’t get some bacterial infections, or if we had genes to attack viruses and parasites. The thing is even if we evolved to have these genes, bacteria and viruses will evolve right back to match us, but it’s a cool thought!

    • Photo: Sarah Montgomery

      Sarah Montgomery answered on 8 Jun 2020:

      Hi Polina,

      I agree that broadly the answer is “no”, as there are many diseases which everyone is susceptible to regardless of their DNA. Off the top of my head, those include alcohol-induced liver damage, most bacterial infections, repetitive strain injury, lots of mental health problems – an obvious example being PTSD – and of course things like heavy metal poisoning. These all stem from something we’ve been exposed to, or something we’ve done, causing harm to our bodies.

      There is an interesting point to be made about how our DNA can *indirectly* cause disease. Say you’re genetically predisposed to try smoking, and then you smoke for 20 years, and then you get lung cancer – is that because of your DNA?

      In the future, maybe doctors will use knowledge about our genomes to warn us about unhealthy behaviours or diseases which we could be more likely to suffer with. The problem is that we’re all so different that it’s generally very hard to pin down exactly what causes these differences in our personalities and behaviour.

      Funnily enough, I recently read a book about the human genome where the author was quite keen to emphasise how “the purpose of DNA is not to cause disease”! We often end up naming genes after diseases they are linked to, when in fact we all have the same gene, it’s just that some versions are more problematic than others.

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