Ask A Scientist© Molecular Biology Archive

name        Heather F.
status      student
age         16

Question -  Does the statement (featured in my biology book titled 
BIOLOGY 5TH EDITION by CAMPBELL, MITCHELL AND REECE), "Moreover a number 
of genes are known to give rise to two or more different proteins, 
depending on which segments are treated as exons during RNA processing," 
contradict that of Tatum's and Beadle's ONE GENE - ONE PROTEIN 
theory/hypothesis?

No, it is the definition  of a gene you are having problem with.  A gene is 
a sequence and if two genes have overlapping sequences it does not mean it 
is the same gene!

Steve Sample
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In science, there are exceptions to every rule. And since Beadle and Tatum's
original hypothesis, we have modified it to say "one gene, one polypeptide".
Recall that not only can different exons in a single gene produce a different
polypeptide, but many functional proteins are made of more than one
polypeptide. An example of this is hemoglobin which is made of 2 alpha and 2
beta polypeptide chains that come together to form the single protein.

van hoeck
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Because one gene does NOT always end up producing just one form of the
protein.

PF
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