Re: [asa] lactose tolerance mutation

From: Don Nield <d.nield@auckland.ac.nz>
Date: Tue Dec 12 2006 - 20:37:39 EST

Reading the article from Jim's link I learnt that it was three mutations
in one population -- and an unspecified number in another population --
having an equivalent effect -- keeping a cratin enzyme active.
Don

Jim Armstrong wrote:

> It sure sounds like the same or an equivalent mutation. This from the
> Washington Post article
> <http://www.washingtonpost.com/wp-dyn/content/article/2006/12/10/AR2006121000781.html>
> :
>
> "Now, researchers have evidence that the domestication of cattle
> thousands of years ago was the key to lactose tolerance emerging
> independently in Europe and Africa."
>
> The easiest explanation is the same mutation. One might speculate
> about a certain susceptibility that allowed one mutation to occur,
> also allowing the same mutation under similar conditions in another
> location.
>
> JimA
>
> Randy Isaac wrote:
>
>> This afternoon I listened to the radio program "The Bible Answer Man"
>> sponsored by the Christian Research Institute. Paul Nelson was the
>> guest. He is very impressive in his style of communication. It was
>> generally the standard ID fare but I was surprised at his answer to
>> one of the call-in questions. The caller asked whether there were any
>> beneficial mutations or if they were all harmful. Paul essentially
>> said none was beneficial and mutations may be neutral at best but
>> neutrality doesn't drive evolution.
>>
>> I wish I could have jumped in and asked about the article that Jack
>> Haas posted on his blog on Dec. 11 (I presume you all regularly check
>> Jack's blog at http://www.asa3.org/weblog/jackhaas/ ) on lactose
>> tolerance. If I understand it correctly this is not only an example
>> of a positive mutation (assuming it is positive to be tolerant of
>> lactose) but also one of convergent evolution. I'm not an expert in
>> this field so I have some questions for those of you who are. Are
>> they implying that the same mutation occurred in different
>> populations to achieve convergence in lactose tolerance? Or are these
>> different mutations? If so, what are the characteristics of the
>> mutations causing this change? Is it silencing a specific protein?
>> Activating a silent one? In general, I would like to know what you
>> think is the significance of this finding.
>>
>> Randy
>

-- 
Donald A. Nield
Associate Professor, Department of Engineering Science
University of Auckland
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Received on Tue Dec 12 20:38:28 2006

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