Re: Why can some people plug their nose without pinching nostrils together?

Q: Why can some people plug their nose without pinching nostrils together? (that is, plug 
their noses so one does not smell anything without pinching their nostrils together) Is this 
hereditary or can anyone learn to do this?

Well, my honest answer is, I don’t know for certain.
There are many traits that have been attributed to genetics that are fun to look at, such as 
tongue rolling, ear waggling, attached versus detached ear lobes, eye-brow lifting, and yes
… nostril flaring and pinching.
That said, it seems that no one has been able to say one way or another in any kind of 
definite way whether these really are genetic or learned (except the attached/detached ear 
lobe… obviously, you can’t learn that!).  It appears that many of these can actually be taught 
and learned although there is certainly some debate about tongue rolling (and I sense 
nostril pinching might fall into this same category).
We are taught basic genetics in school and how to use Punnett squares to look at probability 
of dominant and negative traits presenting themselves as a phenotype and whether these 
traits may be sex-linked or not.  A common school exercise has taught many of us that 
tongue rolling is an example of a single gene trait but is it?
According to the Online Mendelian Inheritance of Man (OMIM) project at Johns Hopkins 
University hosted by the US National Institutes of Health at http://www.ncbi.nlm.nih.gov/
entrez/dispomim.cgi?id=189300  there have been many studies looking at tongue 
rolling, one showing the phenotype as dominant another saying it is recessive and yet 
others showing there is disagreement in twins suggesting no genetic link at all…. There 
even seems to be a distinction by one paper between rolling the tip of the tongue and 
moving the tongue into a clover-leaf shape. The most recent study showed that about 2/3 
of males and females could roll their tongue but that twice as many men as women could 
waggle their ears and that in males tongue rolling and ear waggling seemed to be linked.
Apologies for an indirect and inconclusive answer, but these “tricks” can be fun at parties!

Keith Anderson
Brigham & Women's Hospital, Boston, MA, USA