Why didn't Mendel discover autosomal linkage in peas?

Marty Sachs msachs at uiuc.edu
Tue Mar 15 22:02:16 EST 1994

In article <2m59m3$ffj at controversy.math.lsa.umich.edu> Doug Eernisse
<Doug_Ee at um.cc.umich.edu> writes:
>I've been reading the very interesting newish book entitled 
>"Gregor Mendel's Experiments on Plant Hybrids: A Guided Study"
>by Alain F. Corcos and Floyd V. Monaghan (Rutgers Univ. Press,
>1992). At one point the authors mention that peas have seven
>pairs of chromosomes. It sounds like Mendel chose 22 varieties
>of peas, from which he further selected seven pairs of varieties
>which each differed for a single trait, with one variety
>"dominating." It is truly impressive to read the account of
>how Mendel worked out his conclusions from monohybrid crosses.
>Then he did a bunch of di- and trihybrid crosses, which led
>him to what we call today, his law of independent assortment. These 
>left me wondering why he never found a pair of these traits that
>were linked, i.e., on the same chromosome, particularly if
>peas only have seven pairs of chromosomes. Am I missing something?
>Also, can anyone explain how a simple dominant pattern of
>inheritance is explained at the level of gene expression?

As I understand it, two of the traits that Mendel chose to study are 'linked',
but more than 50 map units apart (so they appeared to be 'unlinked').  

Marty Sachs
USDA/ARS & Agronomy/UIUC    msachs at ux1.cso.uiuc.edu [internet]
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