• Question: Can fish develop Down syndrome or autism From zak

    Asked by Sammy, Zak to Anais, katy, Lauren, Richard, Stuart on 10 Mar 2016.
    • Photo: Anais Kahve

      Anais Kahve answered on 10 Mar 2016:

      Hello, I’m afraid I don’t know much about fish but I can tell you that some animals have been found to behave like autistic humans. It is thought that Down syndrome is specific to humans because it has been found to be caused by a genetic change in humans. But there have been some cases around the world where animals have been diagnosed with the phenotypes of humans with Down syndrome. Maybe one of the other scientists can help you out with this!

    • Photo: Lauren Laing

      Lauren Laing answered on 11 Mar 2016:

      Down Syndrome is caused by a trisomy, this is when humans have three copies of chromosome 21. Fish have very different chromosomes, for example the Zebrafish has 25 pairs of chromosomes, the carp has 52 pairs! Although many fish have lots of chromosomes, their chromosome 21 is not the same as ours, and so I dont think they can have downs syndrome!

      Because Down syndrome is the result of an extra copy of the 21st human chromosome, it is a uniquely human genetic problem. However, animals will have their own genetic problems. Anais is right, there have been some cases where animals have been labelled with the phenotype of Down syndrome, but often genetic interrogation tells us these characteristics are not caused by having three copies of chromosome 21.

      For autism, scientists have reported signs of autism found in fish swimming in water contaminated with psychoactive medications. What they found is patterns of gene activity in the fathead minnows that mimicked those seen in susceptible humans with the developmental disorder.

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