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Molecular systematics - is it all rubbish?

Agneta Guillemot Agneta.Guillemot at historia.umu.se
Tue Jun 13 20:20:13 EST 1995


Most people have never conceived an original idea in their 
entire life. There is no difference between the man on the 
floor in a factory, a schoolteacher or a scientist at a 
university. In a normal job you don't need original ideas. 
But at the university you do. With the explosive increase 
in research in different fields the problem becomes acute. 
It is usually solved by inventing "new methods" i.e.  
intellectual fashion. Molecular systematics is one of those 
fashions.  
 
It solves many problems in biological research. Just sequence  
a gene in a few organisms, run the sequences through a computer,  
out comes a parsimony tree, and you have material for an essay. 
The material to work with is almost indefinite. From beetles to  
hydras, from humans to algae, it just goes on and on. 
 
But it is'nt koscher. Why? There is one vital factor that molecularr 
systematicists never seem to take into account in their work:  
Different species evolve at different rates at different times. 
Evolution is'nt just a clockwork that goes on and on. What if,  
for example, the taxa you want to exclude from a grouping of  
organisms, that you have just discovered, have evolved much faster 
at some previous time? It will be different, and you will jump 
to the wrong conclusions.  
 
Let's face it: Evolution in a species slows down and speeds up at 
different times. Some species are left in the backwater, others 
evolve fast in new evolutionary niches. There is no way of knowing 
what happened when. The molecular clock does'nt exist! 
 
There is only one school of systematics whose theorethical basis 
is untouchable. It is of course cladistics. If you apply cladistic 
methodology to sequence data you come to the right, unquestionable 
conclusions. Most molecular systematicists seem to ignore cladistics. 
I hope this will change. 
 
Thank you for your attention! 
 
Ludvig Mortberg




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