[Taxacom] Blue eyes in humans

[Kenneth Kinman]

Hi James and other Taxacomers,
       Try looking at the paper published by Grant and Lauderdale, 2002
(Annals of Human Biology, Volume 29(6):657-666).  In the earliest 20th
Century, the percentage of blue eyes in the white population of the
United States was about 57.4%.  The percentage among the entire
population was therefore roughly 50%.  
      The same paper says that 33.8% of whites born in the United States
between 1936 and 1951 had blue eyes, so the percentage for the entire
population was probably somewhere between 20 and 30% in that period.
The New York Times in 2006 quotes Dr. Grant as stating that the
percentage of Americans with blue eyes has decreased to about 1 in 6
(i.e,, roughly 17%).             
      One can quibble about just how accurate these percentages are, but
the trend is still clear.  It is clearly due to two factors: (1) an
influx of mainly brown-eyed immigrants during the 20th Century; and (2)
more blue-eyed or mixed-eyed whites having children with the brown-eyed
population (especially as interracial marriage became more and more
common during the latter half of the 20th Century).   
      This trend might not be as pronounced in some areas (which
resisted interracial marriage much longer than in the big cities), but
the trend nation-wide is clearly there.  Members of biology classes at a
northwest Georgia university would not be expected to reflect college
students nationwide (much less the wider population who do not attend
college at all).  
      Blue eyes are certainly not rare, even at 15-20% in the United
States (and higher percentages back in northern Europe).  However, the
downward trend is still there.  People with blue-eyed genes are clearly
having fewer children on average than people who lack blue-eyed genes.
And people with blue-eyed genes marrying people with no blue-eyed genes
have almost no chance of having blue-eyed children.  Either way, the
trend seems pretty clear.   And today one can pretend to be blue-eyed
(with contact lenses) or blond-haired (with hair dyes), but such people
cannot pass on those preferences to their offspring if they are not
genetic traits.  Real blue-eyed blondes (especially in the United
States) are becoming less common, and at the same time, those with fake
blonde hair (and even fake blue-eyes) are increasingly filling that
void.     
         ---------Ken