Left Hand, Left Hand, Right Hand, Right

InvertedHands

Why are some people right-handed and why are some people left-handed? For years it was believed that “handedness” (i.e. if you are left-handed or right-handed) was determined in the fetal brain. Researchers from Ruhr University Bochum in Germany recently suggested that asymmetrical gene expression in the spinal chord might help determine handedness. The researchers looked at gene expression in the spinal chord of fetuses between the eighth and twelfth week of pregnancy. Differences in gene expression on the left and right side could already be detected and those areas of activity correlated with arm and leg movement. The researchers also suggested that differences in left and right gene expression could be due to environmental factors.

The study of changes in genetic expression that occur without changes to genetic sequences is called Epigenetics. Environmental factors can act as a trigger for expression of certain genes both in our fetal development and throughout our lives. It will be interesting to find out more about how environmental factors determine handedness and perhaps we may also find out why left-handed people are superior 🙂

About the Illustration: Watercolor with some Photoshop magic. I kept the illustration pretty basic because handedness is a very basic part of our identity. The title is a play on the first line of the “Foot Book” by Dr. Seuss. It was his birthday a few weeks ago and I have read that book enough times this past year that it’s content might rattle around in my brain for all eternity.

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