[Taxacom] Blue eyes in humans

[Kenneth Kinman]

Dear All,
      I am a bit bored by the Acacia debate (I still think the 2005
Congress in Vienna largely resolved the matter in spite of a vocal
minority still stirring the pot of that particular controversy).
T-shirts will certainly not sway my opinion on that.   ;-)       
      On a totally different subject, I am curious about the percentage
of humans (worldwide) having blue eyes.  I have seen figures ranging
from about 5% to about 22%, but I suspect that very wide range of
figures depends on how one defines "blue eyes".  I suppose the 5% figure
includes eyes that are mainly blue, or even some with some admixture of
green or grey.  On the other hand, the 22% figure probably would also
include a wider range, including hazel eyes, or even brown eyes with
lighter specks.  With several eye color genes involved, it is not
surprising that there is a continuum that sparks considerable semantic
confusion.     
       So it is largely semantic, depending on one's particular
delimitation of what constitutes "blue" eyes.  But however one defines
"blue eyes", their frequency has clearly been decreasing in frequency
over the last century.  Even in the U.S., it has decreased from about a
bit over 50% around 1900 to less than 20% today.  Not surprising as
immigration has more heavily shifted from former areas (like the British
Isles and northwest continental Europe) to other areas of the world
where blue-eyes are relatively rare.              
      Given the recessive nature of blue eyes (and by extension, green,
grey, and various mixtures thereof), should one expect the 20th Century
trend (decrease) to continue, or eventually some sort of stable
equilibrium to emerge (however one defines "blue" eyes)?  Will hazel
eyes increasingly become the new majority in the United States and
northern Europe, where bluer eyes once predominated?    
            ------Ken