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From: "Jason S. Clary" <>
Subject: Re: [DNA] Brown eyes
Date: Tue, 9 May 2006 20:38:12 -0700
References: <4460D7B5.6020302@charter.net> <001301c67393$c73fc5f0$bec79045@Ken1>


One theory is that iris color impacts lens and retinal UV absorbtion and
thus dark eye colors serve the same purpose as dark skin colors.

A test of this theory would be to see if lens clouding and other UV linked
disorders are more common in individuals with light eye colors living closer
to the equator.


----- Original Message -----
From: "Ken Nordtvedt" <>
To: <>
Sent: Tuesday, May 09, 2006 11:09 AM
Subject: Re: [DNA] Brown eyes


> Evolutionary biologist theorists can dream up, especially after the fact,
> a host of possible selection pressures, and I think I have read many if
> not most of them concerning the eye color. But what then makes me wonder
> is why these alleged selection pressures only prevailed in northern
> Europe? As far as I can tell the only place in the world that the blue
> eye thing came to high frequency was the swath of northern Europe from the
> Atlantic to somewhere in Russia. There's lots more temperate and
> sub-arctic zone peoples on earth.
> Ken
>
>
> ----- Original Message -----
> From: "John Lerch" <>
> To: <>
> Sent: Tuesday, May 09, 2006 11:56 AM
> Subject: Re: [DNA] Brown eyes
>
>
>> One thing that no one has brought up in this debate--in an attempt to
>> answer Ken's guesstimate that blue eyes took over in a number of regions
>> despite numerous influxes of brown eyes and therefore must have some
>> selective advantage--is the evolutionary hypothesis: There is an
>> advantage to recessive visual aspect gene characteristics since it can
>> help prevent fathers from disavowing there children. IOW there is a
>> selective disadvantage to the dominant gene. Of course at some point
>> that loses its advantage as too many candidate lotharios also have blue
>> eyes/ pale skin etc.
>> There is also an advantage to blue eyes that in a certain light is a
>> disadvantage--it allows the viewer to see the degree of pupil dilation
>> better. The disadvantage is: Brown eyes look like dilated pupils anyway
>> and brown eyed people look on the average friendlier but with less
>> variability of emotion. In other words all the metaphors about "ice
>> princess", "steeley eyes" etc allude to aloof individuals who have a
>> harder time hiding their aloofness because of their eye color.
>
>
>
> ==============================
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>
>

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