Anyone Seen Evolution?

Ed Rybicki ed at MOLBIOL.UCT.AC.ZA
Tue Nov 19 02:37:25 EST 1996


> To:            mol-evol at net.bio.net
> From:          Jeff Bush <jbush at afit.af.mil>
> Subject:       Re: Anyone Seen Evolution?
> Date:          Mon, 18 Nov 1996 17:02:34 -0500

Jeff trawled...

>... My question was pointing at *observing* a 
> benifitial mutation in the genetic code.

sp: beneficial B-)

And yes, if you take BK virus (a polyomavirus) out of the urine of 
immunosuppressed patients, and cycle it in tissue culture (in which 
it initially refuses to grow), checking it frequently by PCR and 
sequencing, you will find that tissue culture-adapted mutants arise, 
all of which independently have rearranged their "control regions".  
In other words, the viruses mutate at a hot-spot, and the ones which 
are viable come through.  VERY beneficial, for the virus.  And can be 
found in the lit in J Virol by Rubinstein and Harley some years ago.

So sorry, Jeff, one can and does observe beneficial mutations.  
Another is the one(s) which allow Mycobacterium tuberculosis (causes 
TB) to become resistant to certain antibiotics - and yes, one can 
prove it is mutation and not pre-existing sequence by PCRing the 
gene(s) in question before and after seeing the resistance arise in 
culture, making a library, and looking for it/them.

Back to the Book, Jeff....



                     Ed Rybicki, PhD  
      Dept Microbiology     |   ed at molbiol.uct.ac.za   
   University of Cape Town  | rybicki at uctvms.uct.ac.za
   Private Bag, Rondebosch  |  phone: x27-21-650-3265
      7700, South Africa    |   fax: x27-21-689 7573
    WWW URL: http://www.uct.ac.za/microbiology/ed.html      
                                        
    "Out here on the perimeter, there are no stars..."



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