The incidence of left-handedness in people
is about 10%, and that appears to be fairly constant across the world. It is
also known that left-handedness runs in families, which might seem to indicate
that there is a gene that influences whether a child will turn out to be
left-handed. The only problem is that nobody can identify the gene that might
be responsible.
Where does left-handedness comes from?
A study carried out at Nottingham
University conducted detailed genetic analyses of 2,000 pairs of twins, because
it is known that identical twins tend to share handedness more strongly than
non-identical twins. This suggests a genetic link because identical twins have
identical DNA.
However, the conclusion is that there is no
single gene that causes left-handedness, so it might be a combination of genes
that does the trick. The same is apparently true for other human
characteristics such as height and cognitive abilities. It is therefore
improbable that it will ever be possible to predict whether a new-born baby
will turn out to be left-handed by analysing its DNA.
However, the study does appear to have
identified a gene that determines how strongly handed one is, whether left or
right, and this confirms other research done elsewhere. It is rare to find
someone who is entirely left- or right-handed, and there is apparently a
genetic reason for this.
Being left-handed
This is an area that interests me because I
am left-handed (reasonably strongly so); however, because I was adopted I
cannot trace any left-handedness in my natural family, which is unknown to me.
The only person I know who is a blood relative is my son, who is right-handed!
Incidentally, one thing I cannot do
right-handed (apart from writing) is operate a computer mouse! I haven’t switched
the buttons round because my index finger naturally wants to go to the
left-hand button, and right-clicking is no problem. People know when I’ve been
using a computer because of where I leave the mouse!
© John Welford
Left-handed guitarists are left out when it comes to the choice of guitars. Music stores often have only one left-handed guitar model per 100 right hand models.
ReplyDeleteI am left-handed too! Gives me a little sense of pride as there's not that many of us, it seems like. In my family, it runs in the maternal line - my mother, aunt are left-handed, where my brother and father are right-handed.
ReplyDeleteLike you, I write left-handed and use a mouse on the left side. However, I throw a ball and use scissors on my right side. Interesting!