unit-characters

Updated: May 17, 2025

Moreover the principle of unit-characters, the preeminent significance of which has come to be more fully recognized of late, is in full harmony with the theory of sudden mutations. Together these two conceptions go to strengthen the probability of the sudden origin of all specific characters.

Hugo de Vries - Species and Varieties, Their Origin by Mutation

This discussion gives a clear insight into the fundamental phenomena of hybrid fertilization. It at once shows the correctness of the assumption of unit-characters, and of their pairing in the sexual combinations. But Mendel's law is not at all restricted to these simple cases.

Hugo de Vries - Species and Varieties, Their Origin by Mutation

The term balanced crosses then conveys the idea of complete bisexuality, all unit-characters combining in pairs. Unbalanced crosses are those in which one or more units do not find their mates and therefore remain unpaired. This distinction was proposed by Macfarlane when studying the minute structure of plant-hybrids in comparison with that of their parents .

Hugo de Vries - Species and Varieties, Their Origin by Mutation

These physiologic units, which in the end must be the basis for the distinction of the systematic units, may best be designated by the term of "unit-characters." Their internal nature is as yet unknown to us, and we will not now look into the theories, which have been propounded as to the probable material basis underlying them.

Hugo de Vries - Species and Varieties, Their Origin by Mutation

Mendel's law of varietal hybrids is based upon the principle of unit-characters, and the validity of this conception has thus been brought home to many investigators. A study of fluctuating or individual variability, as it was formerly called, is now carried on chiefly by mathematical methods. It is not my purpose to go into details, as it would require a separate course of lectures.

Hugo de Vries - Species and Varieties, Their Origin by Mutation