• Question: why are twins different ? this includes identical and none identical?

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      Asked by samiya to katy on 13 Mar 2016.
      • Photo: Katy Kellett

        Katy Kellett answered on 13 Mar 2016:

        Well it starts at when they are conceived. Identical twins come from one egg which is why they have the same genes and DNA and are therefore always the same gender. Where as non-identical twins come from two eggs which is why they have different DNA and therefore look different.

        But when it comes to personality that all develops when we are born, therefore every twin in totally unique in this way. Basically this means that even if twins share the same DNA the way they use the DNA as they grow can become very different

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    • Photo: Lauren

      Lauren commented on :

      I hope you don’t mind if I add to this!? Katy is right, because identical twins come from the same egg they are genetically identical in terms of their DNA! However, there is a lot of research looking into how identical twins can grow up to be so different! Some of these studies look at twins which were separated at birth, perhaps because of adoption. They then grow up in a different environment, perhaps even in a different country!!

      Twins share the same genes but their environments becomes more different as they age. This unique aspect of twins makes them an excellent chance to understanding how genes and the environment contribute to certain traits, especially complex behaviors and diseases. Scientists are particularly interested in how for twins with exactly the same DNA, one twin could develop a disease which the other doesn’t. A good example is: schizophrenia! Sometimes only one of the twins develops this disease. Scientists are beginning to learn a lot about these diseases because of twin studies, and understanding how they may work. One theory is that something called epigenetics has a role.

      Have you heard of epigenetics? This is basically the study of biological mechanisms that could switch genes on and off, or change the way in which they are expressed. Epigenetics is influenced by the environment in which we live, and is thought to explain some of the differences we see between genetically identical twins! It is quite complex, but really exciting!