Giardia question

A. Kimo Morris morrisk at bcc.orst.edu
Thu Apr 10 18:50:19 EST 1997


Michael J. Bumbulis wrote:
> 
> Here's a question for someone in the know about Giardia.
> They have two nuclei, right?  Well, do the two nuclei
> contain different sets of chromosomes?  And during mitosis,
> do all the chromosomes mix or are the contents of each nucleus
> separated independently?

Good question.  I don't have an answer, but here is some information 
that might help.  Yes, mature motile Giardia have two nuclei.  They 
divide by binary fission (first the nuclei, then the locomotory 
apparatus, then the suction disk, and finally the cytoplasm).  The 
encysting stage can have two or four nuclei depending on how old it is.  
To the best of my knowledge (which admittedly is not much on this 
subject) I don't think the halves (or quarters) have different sets of 
chromosomes.  It's just a gut feeling (no pun intended), but I suspect 
that since they divide by binary fission, that the two halves should 
have equal complaments of stuff.  Of course, how they are programed to 
stop at only having two halves is a mind boggling thought.  Why not have 
8 or 16, or for that matter, a million cells?  Do any microzoo people 
out there have an answer?

Also, no mitochondria, smooth er, golgi bodies or lysosomes have been 
detected in Giardia.  

I hope this helps.

-- Kimo

--------------------------------------------------------------
A. Kimo Morris              |
Department of Entomology    | Office   - (541)737-2453
Oregon State University     | FAX      - (541)737-3643
Cordley Hall 2046           | Internet - morrisk at bcc.orst.edu
Corvallis,OR 97331-2907,USA | http://www.orst.edu/~morriaar
--------------------------------------------------------------
"I hope that some animal never bores a hole in my head and lays
its eggs in my brain, because later you might think you're
having a good idea but it's just eggs hatching" -- Jack Handy



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