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George



Posts: 313
Joined: Feb. 2006

(Permalink) Posted: Nov. 09 2011,15:11   

[quote=Southstar,Nov. 09 2011,08:01][quote=George,Nov. 09 2011,07:55]
Quote (Southstar @ Nov. 09 2011,06:39)
 
Quote (George @ Nov. 09 2011,04:45)
 
Quote (Dr.GH @ Nov. 08 2011,12:23)
     
Quote (Southstar @ Nov. 08 2011,09:39)
Hi,

I've just finished reading a paper in the New Journal of Botany on the evolution and taxonomy of the narrow-leaved marsh orchid complex (within Dactylorhiza) in Britain, Ireland and the rest of Europe.  These have all originated as allopolyploids of the same two diploid species in apparently four separate episodes.  In other words, two species hybridise and the hybrid undergoes genome duplication, which results in instant reproductive isolation (more or less).  Biogeographical and molecular evidence suggests that three species evolved after the last glacial maximum, whereas the fourth predates it.  What's really interesting are the differences in ecological (habitat) preferences shown by these four species, which serves to further isolate each species from the others, setting them on separate evolutionary trajectories.

Hi,

Could you give me a link to the paper.

Thanks
Marty

http://www.ingentaconnect.com/content....rt00002 should work.  If not, let me know and I'll see what I can do.

Hi,

I was about to post it then i read the first line of the study "This subjective and highly personal commentary critically reviews..."

They, the dims, have a thing for picking stuff like this out of even well written papers and with that saying something stupid like... See even the people writing it call it a personal whim "see she's puting out rubbish" ha ha ha. I really need to stay a step or two ahead of them.

Thanks anyway
Marty

I understand and it's unfortunate for your purposes that he prefaces the abstract with those words.  For what it's worth, there's a lot of "critical review" before he gets to the personal opinions.  His review is a good summary of the methods used and issues involved in plant speciation.  Very accessible to the non-molecular specialist, like me.

It also illustrates one of the reasons why the biological species concept is less useful when applied to plants than vertebrates.  Another reason is the presence within some species of reproductive barriers that serve to promote outcrossing.  For example, primroses have flowers in two forms, pin and thrum, differentiated by relative length of stamens and styles.  Plants with pin flowers pollinate those with thrum flowers or vice versa.  Pin to pin or thrum to thrum generally doesn't work.  Are primroses one species or two under the biological species concept?

Edited for more caveatness.

  
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