>I meant that SOME phenotypes are retained irrespective of their adaptive value. 

That is helpful- in the Enbody et al paper there are comparisons made to the results of phenotypical changes in beak size in finches to stature in humans observing:

'... the selection pressures affecting human stature differ from those affecting beak size, which influences the distribution of effect sizes...' and;

'Conditions that vary over time may instead lead to balancing selection and the maintenance of variation, rather than the fixation of beneficial alleles, because of fluctuations in the fitness of alleles at individual loci.'

I take this to generalize two things regarding human adaptation (i.e. eye color):

1. Some traits are maladaptive in most environments for some species (i.e. excessive height in humans) - as such, these traits occur at low frequencies.

2. For folks living in more industrialized areas, humans control a large percentage of their environment (i.e. sunglasses and sunscreen) - the selective pressure related to eye color is attenuated.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html