UNANSWERED QUESTIONS

John Ladasky ladasky at leland.Stanford.EDU
Mon Jun 3 13:07:07 EST 1996


In article <t.chappell-3005961435090001 at t-chappell.mcbl.ucl.ac.uk>,
Tom Chappell <t.chappell at ucl.ac.uk> wrote:
>
>>UNANSWERED QUESTIONS IN BIOLOGY.  27 May 1996
>>
>
>>
>>Question 34:  What is the evidence that each cell of a particular
>>    plant or animal contains the same quantity of DNA?
>>
>Given the tone of the original question, I think I'll take the opportunity
>to rip into this one...
>
>
>There is no evidence because it's a false hypothesis.
>
>Someone asking this question does not understanding (as a start):
>
>1) differences between the G1, S and G2 phases of the cell cycle
>2) meiosis
>3) differentiation of either red blood cells or striated muscle
>4) polytene chromosomes
>5) keratinized epithelium
>6) mitochondria biogenesis
>7) endomitosis
>8) malignant and nonmalignant tumors
>9) apoptosis
>10) gene amplification
>11) retroviruses
>
>Buy a copy of Molecular Biology of the Cell and start at page 1.

	On the other hand, if you confine yourself to the examination
of healthy, diploid G0/G1 cells (which defines an awful lot of tissue),
there is good evidence that the amount of DNA in each cell agrees to
within the limits of measurement.  The measurements are made using 
quantitative fluorescence techniques (e.g., flow cytometry) and a DNA
fluorochrome.
 
-- 
Unique ID : Ladasky, John Joseph Jr.
Title     : BA Biochemistry, U.C. Berkeley, 1989  (Ph.D. perhaps 1998???)
Location  : Stanford University, Dept. of Structural Biology, Fairchild D-105
Keywords  : immunology, music, running, Green



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