Re: [asa] lactose tolerance mutation PS

From: Don Nield <d.nield@auckland.ac.nz>
Date: Tue Dec 12 2006 - 20:57:18 EST

PS: I meant a*certain* enzyme! I also leant from the link in Jack's blog
that there was one European mutation that had the same effect as each of
the three African mutations, -- a good example of multiple convergent
evolution.
Don

Don Nield wrote:

> 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
Private Bag 92019
Auckland 1142, NEW ZEALAND
ph  +64 9 3737599 x87908 
fax +64 9 3737468
Courier address: 70 Symonds Street, Room 235 or 305
d.nield@auckland.ac.nz
http://www.esc.auckland.ac.nz/People/Staff/dnie003/
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Received on Tue Dec 12 20:57:57 2006

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