• Question: Are the genes of twins identical?

    Asked by barrychuckle1 to Madgie, Carla, Nick, Vicky, Werner on 9 Nov 2013.
    • Photo: Carla Turner

      Carla Turner answered on 9 Nov 2013:

      I have to answer this question as I am a twin! My twin is a boy so we can safely say we do not have the same genes, but it really depends on if you are identical or not.

      Twins that are identical are made from one fertilised egg, so one set of DNA. This fertilised egg starts dividing into cells (which will go on to make a baby) and before there are many cells the cells break into two. This leaves two identical balls of cells and they do have the same genes! So yes Identical twins do have identical genes.

      However some twins (like me!) are made from two fertilised eggs and the eggs and sperm have different DNA therefore forming twins which are not identical.

    • Photo: Werner Muller

      Werner Muller answered on 9 Nov 2013:

      identical twins are, but there are differences in how the genes are activated during life based on “epigenetic” changes. Epigenetic changes are those alterations that change gene activation on a longer term without changes in the gene DNA sequence.

    • Photo: Marlene Lorgen

      Marlene Lorgen answered on 11 Nov 2013:

      Following on from Werner’s answer, epigenetic control of gene expression can be influenced by the environment in which an organism is exposed to at different stages in development.

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