The two were mutually exclusive so far as the gamete was concerned.
For on hypothesis every gamete must be pure for one or other of these two characters.
The factor for this or that unit-character is either present in the gamete or it is not present.
The saving grace is with the gamete, and with the gamete alone.
It is the participation of the gamete in the process that is our criterion of what is and what is not heredity.
But any individual sex-cell, or gamete, cannot (according to his view) bear both Dominant and Recessive traits.
What is the relation between gamete and zygote, between zygote and gamete?
But the problem of the way in which characters are distributed from gamete to zygote and from zygote to gamete remained as before.
It is obvious that the chances of R being distributed to a gamete with or without P are equal.
For two series each consisting of four different types of gamete we require a square divided up into 16 parts.