• Question: How do humans genetically modify crops and animals

    Asked by hch student to David, Gemma, Juhi, Matt, Stéphane, Yinka on 13 Mar 2018.
    • Photo: Stéphane Berneau

      Stéphane Berneau answered on 13 Mar 2018:

      Very interesting question about GMOs.
      The genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination.
      Humans could use a virus to inject DNA into cells at the early stage of development. In plants and bateria, the DNA will kept and mixed in their own DNA. However, in animals (and humans), this extra DNA will be present in cytoplasm of the cells and only temporary express until it is degraded. This is way therapeutics can be challenging.
      Do you think GMOs are good or bad?

      For animals, crops and flowers, genes can be selected at a phenotype level (shape, colour, length…).
      Humans have also use mating to select species.
      Did you know that it happened with dog?

    • Photo: Gemma Chandratillake

      Gemma Chandratillake answered on 13 Mar 2018:

      Historically we have modified the genes of crops and animals by selective breeding. This is quite a crude method because we don’t know how many genes we are selecting for, or what the side effects could be for example, lots of dog breeds have genetic diseases because these have been selected for by mistake along with the trait (say, curly hair) that was desired, and the breeds are very inbred.
      Genetic engineering (genetic modification) enables us to be much more precise in the genetic changes that we make, just changing one gene (that we understand well) at a time. There are several different techniques that you can use to engineer changes to the DNA of plants or animals. One that is getting a lot of attention at the moment is called CRISPR-Cas9: https://ghr.nlm.nih.gov/primer/genomicresearch/genomeediting
      Genetic engineering is a technology and therefore is neither “good” or “bad”. It is frustrating that in Europe we just blanket banned all GM food – I think it would have been better to take things case by case and learn what regulation we needed as we went. There are some potentially very good things we could do by genetically engineering crops e.g. make cheap food more nutritious, make crops able to grow in poor soil etc. I don’t think engineering crops to be resistant to weed killer and then spraying them more was a “good” use, but this could have been regulated differently by regulating the weed killer usage for example.
      In people, genetic engineering of stem cells has a lot of promise for treatments for people with genetic diseases. To me, genetic engineering is a tool that we should strive to perfect in terms of its accuracy; the uses can then be considered one at a time as to whether we consider them reasonable or not. It is interesting though that there is very little regulation of selective breeding, which fundamentally changes the genetics of crops and animals too.

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