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Vries, Hugo de, 1848-1935

"Species and Varieties, Their Origin by Mutation"


In the case of retrogressive changes the visible modification is due, at
least in the best known instances, to the reduction of an active quality
to a state of inactivity or latency. Now if we make a cross between a
species and its variety, the differentiating character will be due to
the same internal unit, with no other difference than that it is active
in the species and latent in the variety. In the hybrid these two
corresponding units will make a pair. But while all other pairs in the
same hybrid individuals consist of like antagonists, only this pair
consists of slightly unlike opponents.
This conception of varietal crosses leads to three assertions, which
seem justifiable by actual experience.
First, there is no reason for a diminution of the fertility, as all
characters are paired in the hybrid, and no disturbance whatever ensues
in its internal structure. Secondly, it is quite indifferent, how the
two types are combined, or which of them is chosen as pistillate and
which as staminate parent. The deviating pair will have the same
constitution in both cases, being [278] built up of one active and one
dormant unit. Thirdly this deviating pair will exhibit the active unit
which it contains, and the hybrid will show the aspect of the parent in
which the character was active and not that of the parent in which it
was dormant.


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