Curved thumb

jwinters at jwinters at
Thu Oct 17 14:09:39 EST 1996

In article <32627538.0 at>, tarolove at
(TaroLover) writes:
> My student is a twin, he has a right curved thumb and left straight
> thumb. But his elder btother has a left curved thumb and right
> straight thumb. But their father and mother are both right straight
> thumb and left straight thumb.
> How to explain the above event?
> Would any Biology experts can answer my question, please send me a
> E-mail. Thank You! :)

First, I wouldn't classify myself as a biology expert.
Second, are these twins identical or fraternal?  If they're fraternal, it
wouldn't be suprising that they have differences such as this one.  If
they are identical, however, this might fall under the category of mirror
twinning.  This simply means for whatever trait (curved/straight thumbs
in this case), the identical twins are mirror images of each other.
Identical twins are never perfectly identical anyway.  HTH.

Jenny Winters
Ph.D. candidate
Department of Human Genetics
Medical College of Virginia

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